NOMENCLATURAL NOTE ON A THECADINIUM SPECIES (DINOPHYCEAE,GONYAULACALES), WHICH WAS DESCRIBED AS NEW INDEPENDENTLY THREE TIMES WITHIN TWO MONTHS1

Three Thecadinium species, independently described as new in three separate publications, are actually regarded as conspecific. The combined plate formula is Po 3′ 1a 6″ 5‐7/8c 5s 6″′ 2″″. The size range of the species is 38–65 l m in length and 23–42 lm in depth. It has one or two strongly lobed chloroplasts. The correct name of the species is Thecadinium yashimaense Yoshimatsu, Toriumi et Dodge 2004. Thecadinium mucosum Hoppenrath et Taylor 2004 and Thecadinium foveolatum Bolch 2004 are taxonomical synonyms. This note clarifies the plate tabulation and other features of the species.     

Molecular characterization and identification of markers for toxic and non-toxic varieties of <Emphasis Type="Italic">Jatropha curcas</Emphasis> L. using RAPD,AFLP and SSR markers

Jatropha curcas L., a multipurpose shrub has acquired significant economic importance for its seed oil which can be converted to biodiesel, is emerging as an alternative to petro-diesel. The deoiled seed cake remains after oil extraction is toxic and cannot be used as a feed despite having best nutritional contents. No quantitative and qualitative differences were observed between toxic and non-toxic varieties of J. curcas except for phorbol esters content. Development of molecular marker will enable to differentiate non-toxic from toxic variety in a mixed population and also help in improvement of the species through marker assisted breeding programs. The present investigation was undertaken to characterize the toxic and non-toxic varieties at molecular level and to develop PCR based molecular markers for distinguishing non-toxic from toxic or vice versa. The polymorphic markers were successfully identified specific to non-toxic and toxic variety using RAPD and AFLP techniques. Totally 371 RAPD, 1,442 AFLP markers were analyzed and 56 (15.09%) RAPD, 238 (16.49%) AFLP markers were found specific to either of the varieties. Genetic similarity between non-toxic and toxic verity was found to be 0.92 by RAPD and 0.90 by AFLP fingerprinting. In the present study out of 12 microsatellite markers analyzed, seven markers were found polymorphic. Among these seven, jcms21 showed homozygous allele in the toxic variety. The study demonstrated that both RAPD and AFLP techniques were equally competitive in identifying polymorphic markers and differentiating both the varieties of J. curcas. Polymorphism of SSR markers prevailed between the varieties of J. curcas. These RAPD and AFLP identified markers will help in selective cultivation of specific variety and along with SSRs these markers can be exploited for further improvement of the species through breeding and Marker Assisted Selection (MAS).     

Ingestion of the dinoflagellate, Pfiesteria piscicida, by the calanoid copepod, Acartia tonsa

The dinoflagellate, Pfiesteria piscicida, can form harmful algal blooms in estuarine environments. The dominant copepod species usually found in these waters is Acartia tonsa. We tested the ability of A. tonsa to graze the non-toxic zoospore stage of P. piscicida and thus serve as a potential biological control of blooms of this algal species. A. tonsa grazed the non-toxic zoospore stages of both a non-inducible P. piscicida strain (FDEPMDR23) and a potentially toxic strain (Tox-B101156) at approximately equal rates. Ingestion of P. piscicida increased with cell concentration and exhibited a saturated feeding response. Both the maximum number of cells ingested (I_max) and the slope of the ingestion curve (α) of A. tonsa feeding on P. piscicida were comparable to these ingestion parameters for A. tonsa fed similar-sized phytoplankton and protozoan species. When these laboratory ingestion rates were combined with abundance estimates of A. tonsa from the Pocomoke Estuary and Chesapeake Bay, we found that significant grazing control of the non-toxic zoospore stage of P. piscicida by A. tonsa would only occur at high copepod abundances (>10 copepods L⁻¹). We conclude that under most in situ conditions the potential biological control of blooms of P. piscicida is exerted by microzooplankton grazers. However, in the less saline portions of estuaries where maximum concentrations of copepods often occur with low abundances of microzooplankton, copepod grazing coefficients can be similar to the growth rates of P. piscicida.     

Species-diagnostic markers in <Emphasis Type="Italic">Larix</Emphasis> spp. based on RAPDs and nuclear,cpDNA, and mtDNA gene sequences,and their phylogenetic implications

Genetic markers from the nuclear, chloroplast, and mitochondrial genomes were developed to distinguish unambiguously among four larch species [Larix laricina (Du Roi) K. Koch, Larix decidua (Mill.), Larix kaempferi (Lamb.) Sarg., and Larix sibirica (Ledeb.)] used in intensive forestry in eastern North America. Nine random amplified polymorphic DNA (RAPD) fragments had good diagnostic value, and 3 out of 12 nuclear genes were found to harbor fixed interspecific polymorphisms implicating a total of 17 single nucleotide polymorphisms (SNPs) and 2 indels. The sequencing of five mtDNA introns (cox1-intron1, matR-intron1, nad1-intron b/c, nad3-intron1, and nad5-intron1) and four cpDNA regions (matK, trnL-intron, trnT–trnL and trnL–trnF intergenic spacers) resulted in the identification of 14 sites with fixed interspecific differences among the four species. Including the ten Larix species, one polymorphic site per 47 nucleotide sites sampled was observed for nuclear genes, one per 283 sites for cpDNA, and one per 374 sites for mtDNA. The phylogeny of the genus could be estimated from variation among the ten species detected in two cpDNA intergenic regions and four mtDNA introns. There was congruence between cpDNA and mtDNA phylogenies with three large groups delineated: the North American, North Eurasian, and South Asian taxa. The position of L. sibirica differed between organelle genomes. It was regrouped with South Asian species on the cpDNA tree, but with its North Eurasian congenerics on the mtDNA tree. To simplify the detection of diagnostic DNA sequence polymorphisms among the four main Larix species, cleaved amplified polymorphic sequence (CAPS) assays were developed from the polymorphisms identified in the various genomes. Seventeen primer–enzyme combinations were tested, and six were selected for their high level of informativeness. These new species-specific diagnostic markers should be useful for the certification of larch breeding materials and hybrid stocks used in intensive forestry in the northern hemisphere.     

Mixotrophy in the sand-dwelling dinoflagellate Thecadinium kofoidii

Thecadinium kofoidii is a marine sand-dwelling dinoflagellate that sometimes forms dense blooms. This species was previously thought to be an exclusively autotrophic dinoflagellate, and its mixotrophic ability has not been explored yet. By investigating its ecophysiology, its trophic mode should be revealed. We explored the mixotrophic ability of T. kofoidii by examining its protoplasm under light and transmission electron microscopes with diverse algal prey species. Furthermore, the feeding mechanism of T. kofoidii and prey species on which it feeds were investigated. In addition, the growth and ingestion rates of T. kofoidii as a function of prey concentration were determined when feeding on the benthic cryptophyte Rhodomonas salina. Thecadinium kofoidii was able to feed on R. salina and the dinoflagellate Symbiodinium voratum, which had equivalent spherical diameters (ESDs) ≤ 10.1?µm, while it did not feed on the benthic dinoflagellates Levanderina fissa, Prorocentrum concavum or Ostreopsis cf. ovata, which had ESDs ≥ 15?µm. Thecadinium kofoidii fed on the edible prey cells using the peduncle. The maximum ingestion rate of T. kofoidii on R. salina was 1.3 cells predator^?1 d^?1. However, feeding on R. salina did not significantly increase the growth rate of T. kofoidii. The low ingestion rate of T. kofoidii on R. salina may have partially resulted in the lack of significant increase in its growth rate due to mixotrophy. The present study discovered predator–prey relationships between T. kofoidii and R. salina and S. voratum, which may change our view of the energy flow and carbon cycling in marine benthic food webs.     

DESCRIPTION OF THECADINIUM MUCOSUM SP. NOV. (DINOPHYCEAE), A NEW SAND‐DWELLING MARINE DINOFLAGELLATE,AND AN EMENDED DESCRIPTION OF THECADINIUM INCLINATUM BALECH1

A new thecate, phototrophic, marine, sand‐dwelling dinoflagellate, Thecadinium mucosum Hoppenrath et Taylor sp. nov., is described from a culture isolated from Boundary Bay, British Columbia, Canada. It was illustrated with LM as well as SEM and TEM, and its position in the phylogenetic tree of dinoflagellates was investigated using molecular methods. Cells are asymmetrical, oval, laterally flattened, and strongly pigmented, with the plate formula P 3′ 1a 6′′ 7/8c 5 s 6′′′ 2′′′′. Thecal plates are smooth with scattered pores, and there is a distinctive anterior intercalary plate that could be involved in mucus secretion. Thecadinium inclinatum Balech (=Sabulodinium inclinatum (Balech) Saunders et Dodge), a thecate, marine, sand‐dwelling species that has been previously confused with what we now call T. mucosum, was also examined and illustrated through LM and SEM. New information on T. inclinatum is provided, including its plate formula P 3′ 6′′ 7c ?s 5′′′ 1p 1′′′′; we consider T. inclinatum to be related to most other Thecadinium species and not to Sabulodinium. Molecular phylogenetic analyses based on the small subunit ribosomal gene of T. mucosum, T. kofoidii (the type species of the genus), and T. dragescoi weakly support earlier suspicions based on morphology that T. dragescoi is not a member of Thecadinium. Tabulational patterns of the species suggest a relationship to the genus Amphidiniopsis.     

Morphology and taxonomy of five marine sand-dwelling Thecadinium species (Dinophyceae) from Japan, including four new species: Thecadinium arenarium sp. nov., Thecadinium ovatum sp. nov., Thecadinium striatum sp. nov. and Thecadinium yashimaense sp. nov.

Thecadinium inclinatum Balech and four new marine sand‐dwelling species of the dinoflagellate genus Thecadinium are described from the sandy beaches along the coast of Shikoku, Japan. Thecadinium inclinatum is thecate, bilaterally flattened, elliptical in shape, non‐photosynthetic, and measures 55–75 μ in length and 43–59 μ in depth. The epi‐ and hypotheca theca are semielliptical and the thecal surface is smooth with small pores. The plate formula is Po (pore plate), 3′, 7″,?c,?s, 5″′1″′.Thecadinium ovatum sp. nov. is thecate, non‐photosynthetic, bilaterally flattened and almost oval in lateral view. The cell measures 40–50 μm in length and 33–40 μm in depth. The hypotheca has two or three strong antapical spines. The plate formula is 3′, 6″,6c, 5s?, 5″′, 1″′. Thecadinium striatum sp. nov. is thecate, non‐photosynthetic, bilaterally flattened and somewhat elliptical in lateral view. The cell is 33–41 μm long and 23–30 μm deep. Several striae are present on the hypotheca. The plate formula is 3′, 6″, 6c, 5s?, 5″′, 1″″. Thecadinium yashimaense sp. nov. is bilaterally flattened, photosynthetic and elliptical in ventral view. The cell is 44–65 μm long and 23–36 μm wide. The thecal surface is smooth with small pores. he cingulum forms a steep left–handed spiral. The plate formula is Po, 3′, la, 6″, 5c, 4s, 5″′, 1″′. Thecadinium arenarium sp. nov. is somewhat wedge‐shaped in ventral view, photosynthetic with brownish chloroplasts and almost rounded in cross section. The cingulum forms a steep left‐handed spiral. The cell measures 35–41 μm in length and 25–30 μm in width. The thecal surface is weakly reticulated with small pores. The hypotheca is conical. The plate formula is Po, 3′, la, 6″, 5c, 4s, 5″′, 1″″.     

<Emphasis Type="Italic">Ambrosiella</Emphasis><Emphasis Type="Italic">beaveri,</Emphasis> sp. nov., Associated with an exotic ambrosia beetle, <Emphasis Type="Italic">Xylosandrus mutilatus</Emphasis> (Coleoptera: Curculionidae,Scolytinae), in Mississippi,USA

Xylosandrus mutilatus is an Asian ambrosia beetle that has recently established in Mississippi, Texas, Alabama, and possibly Florida, USA. We investigated the fungi associated with the mycangia (specialized fungus-transporting structures) of X. mutilatus in Mississippi. Mycangia consistently yielded an Ambrosiella sp. which was subsequently found to be closely related to, but distinct from, other Ambrosiella species affiliated with Ceratocystis. This Ambrosiella is described herein as Ambrosiella beaveri sp. nov. Also isolated were Geosmithia lavendula, G. obscura, and a yeast, Candida homelintoma. It is likely Ambrosiella beaveri was introduced along with the beetle into North America.     

The frequency of multiple paternity in bumble bee (<Emphasis Type="Italic">Bombus</Emphasis>) colonies based on microsatellite DNA at the B10 locus

Summary This study used the microsatellite locus B10 to determine the frequency of colonies with multiple patrilines in a previously unexamined group, the North American bumble bees (Bombus). The effective mating frequency (m_e) was greater than 1 in six of 28 colonies. Five of 11 species tested showed at least one incidence of polyandry: four species from the subgenus Pyrobombus (B. bimaculatus, B. impatiens, B. mixtus, B. ternarius) and one species from the parasitic subgenus Psithyrus (B. citrinus). The B10 locus showed high cross-species amplification success for North American Bombus.     

Phylogeography and genetic relationships of North African <Emphasis Type="Italic">Bufo mauritanicus</Emphasis> Schlegel, 1841 estimated from mitochondrial DNA sequences

Genetic variation within the North African toad Bufo mauritanicus was estimated by sequencing partial 12S rRNA and 16S rRNA mitochondrial regions from widespread populations in Morocco, Algeria and Tunisia. Unlike many other wide ranging species from this area, B. mauritanicus demonstrated very low levels of intraspecific variation. The minimal intraspecific genetic variation may be due to a relatively recent, possibly post-glacial, expansion into its current range. Further phylogeographic studies of other North African species are needed to assess if this is a common biogeographical phenomenon. Phylogenetic analyses support immunological data that B. mauritanicus is part of a clade of predominantly sub-Saharan Bufo, recently assigned to a new genus Amietophrynus. Two different lineages within this clade, B. mauritanicus and the B. pardalis group, appear to have reverted from 20 chromosomes to the more typical 22 chromosomes found in most other Bufonids. However, the alternative hypothesis that the Bufo species with 20 chromosomes form a monophyletic lineage cannot be rejected.     

Distribution and Identification of an Invasive Gracilaria Species that is Hampering Commercial Fishing Operations in Southeastern North Carolina, USA

A newly abundant Gracilaria species in the sounds of southeastern North Carolina has become a problem for commercial fishing and industries drawing water from the lower Cape Fear River. DNA sequence analyses have shown that this species is Gracilaria vermiculophylla, a taxon originally described from East Asia. Surveys for G. vermiculophylla have shown that it has a discontinuous distribution in the sounds of southeastern North Carolina, and suggest that it is spreading. Gracilaria vermiculophylla meets 6 of the 10 criteria used to help identify invasive species in that it has only recently appeared in southeastern North Carolina; is associated with human mechanisms of dispersal; has a restricted distribution; has disjunct populations in isolated oceans; no means of active dispersal, and an exotic evolutionary origin. The species may also meet two additional criteria as its local range is believed to be expanding, and it is filling a previously unoccupied seasonal niche. These factors taken together strongly suggest that G. vermiculophylla is an invasive species in southeastern North Carolina.     

First report of the oriental shrimp <Emphasis Type="Italic">Palaemon macrodactylus</Emphasis> Rathbun, 1902 (Decapoda,Caridea, Palaemonidae) from German waters

The native East Asian shrimp Palaemon macrodactylus has become a common inhabitant of estuaries along the Pacific coast of North America. More recently (documented since 1999), the species has also been colonising European waters and has been reported from Spain, England, Belgium and the Netherlands. In this study, we present a chronology of the reported introductions of this species and provide the first detailed report of its occurrence in German waters. P. macrodactylus was found in the Geeste river mouth (Weser Estuary) as well as in Hooksiel, north of Wilhelmshaven between 2004 and 2005. We assume its presence in other estuarine habitats of the North Sea and predict its introduction into the Baltic Sea.     

Virulence of entomopathogenic hypocrealean fungi infecting <Emphasis Type="Italic">Anoplophora glabripennis</Emphasis>

Twenty isolates of four species of entomopathogenic hypocrealean fungi (Beauveria bassiana, Beauveria brongniartii, Isaria farinosa, and Metarhizium anisopliae) were found to be pathogenic to adults of the Asian longhorned beetle, Anoplophora glabripennis. Survival times for 50% of the beetles tested (ST₅₀) ranged from 5.0 (M. anisopliae ARSEF 7234 and B. brongniartii ARSEF 6827) to 24.5 (I. farinosa ARSEF 8411) days. Screening studies initially included strains of B. brongniartii, which is registered as a microbial control agent in Europe, Asia and South America but not in North America. At that time, we could not confirm that this fungal species is native to North America which added uncertainty regarding future registration of this species for pest control in the USA. Therefore, subsequent bioassays documented median survival times for three M. anisopliae isolates (5–6 days to death) and two of these isolates are suggested for further development because they are already registered for pest control in the USA. An erratum to this article can be found at     

Host Specificity of the Argentine Root-Boring Weevil, Heilipodus ventralis (Coleoptera: Curculionidae), a Potential Biocontrol Agent for Snakeweeds (Gutierrezia: Asteraceae) in Western North American Rangelands—U.S. Quarantine Tests

Native snakeweeds, especially Gutierrezia sarothrae (Pursh) Britton and Rusby and Gutierrezia microcephala (DC.) A. Gray, are among the most widespread and damaging weeds of rangelands in the western United States and northern Mexico. The genus long ago spread to southern South America, where further speciation occurred. We have found several species of insects in Argentina that damage other species of snakeweeds there and are possible candidates for biological control in North America. The first of these, the root-boring weevil, Heilipodus ventralis (Hustache), was tested in Argentina and then sent to the USDA-ARS Insect Quarantine Facility at Temple, Texas, for host specificity testing on North American plants. We tested H. ventralis on 40 species of the family Asteraceae, in 19 tests of five types, using 686 adults and 365 larvae. Host specificity increased from adult feeding, to ovipositional selection, to larval development. At Temple, adults fed mostly on 6 species of the closely related genera Grindelia, Gutierrezia, and Gymnosperma, but with substantial feeding on four other genera of the two preferred subtribes Solidagininae and Machaerantherinae and on Baccharis in the tribe Baccharidinae, with lesser feeding on the subtribe Asterinae, all in the tribe Astereae, and on 1 species in the tribe Anthemideae. Females oviposited primarily on the same 6 species but very little on plants outside the 2 preferred subtribes. Larvae developed only on 9 of the 29 U.S. plant species tested, 6 within the two preferred subtribes and on Brickellia and Aster in other tribes. Only 5 species of three genera appear to be potential true hosts of H. ventralis in North America, on which all stages of the life cycle, adult feeding, oviposition, and larval development, can take place; these are Gymnosperma glutinosum (Spreng.) Less., Gutierrezia grandis Blake, Gut. microcephala, Gut. sarothrae, and Grindelia lanceolata Nutt. None of these genera contain species of economic or notable ecological value; the few rare species appear to be protected by habitat isolation from attack by H. ventralis. H. ventralis, therefore, appears sufficiently host specific for field release in North America. This is the first introduced biocontrol agent to be approved for release in a continental area to control a native weed.     

The benthic macro-algae of Georgian Bay,the North Channel and their drainage basin

Thirty-nine subgeneric taxa of macroalgae have been collected from 83 sites in Georgian Bay, the North Channel and their drainage basin. There were 15 species in the Bay and Channel and 32 species in streams, rivers and impoundments in the basin. Only 8 of the Bay and Channel species were also found in the watershed. Cladophora glomerata was the most important species in Georgian Bay and the North Channel, having an estimated 640 × 10³ m² cover and 19 × 10⁴ kg fresh weight standing crop. However, this species was largely concentrated on the southwestern shorelines of these water bodies. Its distribution along the northeastern shoreline appears to be limited by total ion and phosphorus levels. Chara globularis/vulgaris was the subdominant taxon in Georgian Bay and the North Channel with an estimated 70 × 10³ m² cover and 15 × 10³ kg fresh weight biomass. This species was more widely distributed than C. glomerata. No other taxon contributed significantly to the standing crop including the frequently occurring Ulothrix zonata, Zygnema spp. and Spirogyra spp. The maximum benthic macroalgal biomass was estimated to be approximately 10% of the phytoplankton biomass.     

<Emphasis Type="Italic">Bathyphellia margaritacea</Emphasis> (Cnidaria: Actiniaria): the most northern species of the world

The sea anemone Bathyphellia margaritacea (Danielssen in Actinida. The Norwegian North-Atlantic expedition 1876–1878, Groendahl, Oslo, 1890) was collected by the research submersible MIR at the North Pole at a depth of 4,262 m and by the North Pole Drifting Station NP-22 in the American sector of Arctic Ocean covered by permanent ice. These widely separated records significantly increase the known geographic range of the species. B. margaritacea is highly plastic and has an ability to occupy different types of substrates. It appears to be the only species of sea anemone that is able to range in the high Arctic up to the North Pole and the only reliably identified species known from this part of the world.     

A revision of <Emphasis Type="Italic">Anisochilus</Emphasis> Wall. ex Benth. (Lamiaceae)

Summary  Sixteen species of Anisochilus are reviewed. Full synonymy, information about types, distributions, and a key to species are given. The type of the little known A. adenanthus Dalzell has been found and the widely used A. verticillatus is a synonym. A. sericeus and A. dysophylloides var. purpureus are synonyms of A. dysophylloides. A. henryi, a recently published name is a synonym of A. robustus. Nine names are lectotypified. The genus occurs in South Asia, from the East Himalaya, North Thailand, and South China in the North to Sri Lanka and Peninsular Thailand in the South.     

Diet and seed removal rates by the harvester ants Pogonomyrmex rastratus and Pogonomyrmex pronotalis in the central Monte desert, Argentina

Granivorous animals, through seed consumption, may have an important influence on plant abundance, distribution and species composition in desert ecosystems. The aims of this study are twofold: to quantify the diet of Pogonomyrmex rastratus (Mayr) and pogonomyrmex pronotalis (Santschi), and to estimate seed removal per colony of both species throughout their activity season (October-April) in the central Monte desert, Argentina. Both species rely heavily upon seeds, which account for 87–94 % of the items carried to the nests. Their diets are similar, consisting mainly of grass seeds, which represent more than 93 % of the seeds. Among them, three species predominate: Aristida spp., Trichloris crinita and Pappophorum spp. Seasonal variations as well as seed species richness in the diet are also similar between species. However, their food-handling behaviour differs: most caryopses carried by P. pronotalis bear bracts whereas most caryopses carried by P. rastratus lack them. Seed removal per colony by P. rastratus (6 × 10⁴ seeds/colony) and by P. pronotalis (5 × 10⁴ seeds/colony) throughout the season is similar to the one reported for P. occidentalis in North America. However, seed removal per hectare, which could be estimated for P. rastratus (8.3 × 10⁵ seeds/ha), is lower than removal rates reported for the North American species P. barbatus, P. desertorum, P. rugosus and P. californicus, probably because P. rastratus has lower activity levels and smaller colonies than the North American studied species. Received 6 April 2005; revised 1 September 2005; accepted 2 September 2005.     

New records and distributions of two North American branchiobdellidan species (Annelida: Clitellata) from introduced signal crayfish, <Emphasis Type="Italic">Pacifastacus leniusculus,</Emphasis> in Japan

This is the first report of two North American branchiobdellidans, Sathodrilus attenuatus Holt, 1981, and Xironogiton victoriensis Gelder and Hall, 1990, on the signal crayfish, Pacifastacus leniusculus (Dana, 1852) introduced into Japan from the Columbia River system, northwestern North America. Signal crayfish from 12 localities in eastern and northern Hokkaido, Japan, were examined and each supported S. attenuatus. In addition, an individual of this species was found on preserved material from Ishikawa Prefecture, central Honshu. All of these branchiobdellidans reported in Hokkaido most probably came from the original population of signal crayfish introduced into Lake Mashu, Hokkaido, Japan, in 1930. It is suggested that the use of non-pathogenic branchiobdellidans, when present, provides an easy method for tracing the spread of crayfishes around Japan and could also be applied in other countries and continents. Specimens of X. victoriensis were only found on crayfish in a stream at Akashina in Nagano Prefecture, central Honshu, Japan. Although the signal crayfish appears to be displacing the endemic Japanese crayfish, C. japonicus, no native branchiobdellidans were found on any of the introduced signal crayfish examined.     

Observations on the morphology of some North American nemertines with consequent taxonomic changes and a reassessment of the architectonics of the phylum

A majority of the nemertine species from the western North Atlantic were originally described from life in the nineteenth century. Many of these were established by A. E. Verrill who had ‘an eye for species’ no matter which phylum he was working with, and thus when living nemertines which he described are encountered, they can usually be recognized. The morphology of most of these species has never been reported; some may prove to be species described earlier from the eastern North Atlantic. Morphological observations on the nemertine species from the North East coast of the Pacific are inadequate and have prevented satisfactory comparison with species from Japan and eastern Russia. The morphology of some species collected in the Gulf of Maine and from Cape Cod, as well as a re-examination of some of the slides of type specimens of species from the west coast of North America, indicates that their generic placement must be re-examined. The architectonic plan of the heteronemertines postulated over 100 years ago can not be substantiated and is redescribed. Three new heteronemertean genera are described: Tenuilineus gen.n. Parvicirrus gen.n., Tarrhomyos gen.n.