LABYRINTH AND EQUILIBRIUM : I. A COMPARISON OF THE EFFECT OF REMOVAL OF THE OTOLITH ORGANS AND OF THE SEMICIRCULAR CANALS.

1. A dogfish from which all six ampullæ have been removed maintains its equilibrium; the righting reactions occur promptly; compensatory movements of the eyes occur in response to rotations in all planes except the horizontal; the compensatory position of the eyes is retained if the animal is held in an abnormal position. Both the static and dynamic functions of equilibrium continue, therefore, after complete removal of all the semicircular canals and all the ampullæ. 2. After complete removal of the otoliths from the vestibules without injury to the ampullæ the animal maintains its equilibrium in the water, rights itself promptly, and makes compensatory motions to rotations in all planes. If held in an abnormal position the compensatory position of the eyes is maintained. Both static and dynamic functions of equilibrium continue. 3. Destruction of both the semicircular canals and the otolith organs completely abolishes all compensatory movements and equilibrium reactions of labyrinthine origin. 4. It is pointed out that these observations do not justify the theory of Mach and Breuer that the ampullæ and semicircular canals are the organs for the dynamic functions of equilibrium, and that the otoliths are the organs for the static functions of equilibrium. 5. The new experiments recorded in this paper show that the ampullæ alone (without the otoliths) suffice for all the dynamic and all the static functions of equilibrium of the ear; and that the otolith organs (without the ampullæ) suffice for all the static and for all the dynamic functions of equilibrium of the ear with the exception of the response to a rotation of the animal in a horizontal plane.     

THE PROTOPLASMIC ULTRASTRUCTURE OF THE VEGETATIVE CELL OF MELOSIRA VARIANS C. A. AGARDH1

A detailed fine structural study of the nondividing vegetative cell of the centric diatom Melosira varians reveals peripheral organization of cytoplasm and organelles around a central vacuole. Polarity of the cell is such that the nucleus is found at the valve face of the epitheca. The unusual shape of the nucleus and its associated microtubular system and polar body are thought to relate to the migration of the nucleus during other phases of cell growth. Unusual discontinuities of the plastid lamellae are reported and the significance of the periplastid reticulum is discussed. Possible roles for the cytoplasmic vesicles and the membrane system in the cell are also considered.     

THE ULTRASTRUCTURE OF LICHENS. I. A GENERAL SURVEY

The fine structure of 10 lichens was examined. A comparison was made of the storage products of the algal symbiont (Trebouxia) in situ in the desiccated and hydrated states of the lichens. All the Trebouxia phycobionts, with the exception of that in Usnea strigosa, had lipid-containing globules in the pyrenoid. The globules were present in both the hydrated and desiccated conditions. Trebouxia in the hydrated condition contained starch granules in the chloroplast as well as the lipid-containing globules in the pyrenoid. The cell wall of Trebouxia consists of an outer electron-dense layer and an inner electron-light layer. Fungal haustoria (in Lecanora rubina) rupture the outer layer of the algal cell wall and invaginate the inner layer. A thick polysaccharide fibrillar material surrounds the fungal cells. Many bacteria were observed within this material. Septa and lomasomes are described. Ellipsoidal bodies, which appear to be an integral and unique part of the lichen fungal ultrastructure, were observed associated with membrane profiles.     

A REINTERPRETATION OF THE ONTOGENY OF THE ASCOCARP OF SPECIES OF THE ERYSIPHACEAE

A study of four species of Erysiphaceae (Uncinula salicis, Podosphaera leucotricha, Erysiphe cichoracearum, and Microsphaera diffusa) revealed that the binucleate stages of the ascocarp are initiated in a similar manner to those of Diporotheca rhizophila Gordon & Shaw. The “appendages” developing on immature ascocarps are considered to be receptive hyphae. Appendages characteristic of mature ascocarps are produced much later. Lysis of certain centrum cells occurs, and asci are initiated from some of the remaining binucleate centrum cells. Resorption of centrum cells by the asci is supported by this investigation, corroborating Björling's earlier studies on Erysiphe graminis.     

STUDIES IN THE VISCACEAE. II. A REINVESTIGATION OF THE FEMALE GAMETOPHYTE OF ARCEUTHOBIUM DOUGLASII

A reinvestigation of the female gametophyte of Arceuthobium douglasii showed that the development conforms to the Allium type (bisporic), and the report of tetrasporic development is erroneous.     

THE USE OF SOLUBILITY AS A CRITERION OF PURITY OF PROTEINS : I. APPLICATION OF THE PHASE RULE TO THE SOLUBILITY OF PROTEINS. II. THE SOLUBILITY CURVES AND PURITY OF CHYMOTRYPSINOGEN

1. The conditions under which the phase rule may be applied to systems containing proteins are formulated. 2. An attempt was made to fractionate chymotrypsinogen, by crystallization in stages with increasing concentration of magnesium sulfate. No significant fractionation of the protein was achieved, but a small amount of impurity which affects the solubility, while having little influence on other properties of the material, was concentrated in the fractions first precipitated. 3. The solubility of the final fraction was independent of the amount of the saturating solid, from the first appearance of a solid phase, in solvents of three different pH''s. The solubility was independent of the environment in which the crystals were formed (within the limits in which crystallization can be carried out) and the same value was reached from the supersaturated as from the undersaturated side. This material, therefore, conforms closely with the phase rule criteria of a pure protein.     

THE KINETICS OF PENETRATION : V. THE KINETICS OF A MODEL AS RELATED TO THE STEADY STATE

An organic potassium salt, KG, passes from an aqueous phase, A, through a non-aqueous layer, B, into a watery solution, C. In C it reacts with CO₂ to form KHCO₃. The ionic activity product (K) (G) in C is thus kept at such a low level that KG continues to diffuse into C after the concentration of potassium becomes greater in C than in A. Hence potassium accumulates in C, the osmotic pressure rises, and water goes in. A steady state is eventually reached in which potassium and water enter C in a constant ratio. The rate of entrance of potassium (with no water penetrating into C) may fall off in a manner approximately exponential. But water enters and may produce an exponential decrease in concentration. This suggests that the kinetics may be treated like that of two consecutive monomolecular reactions. Calculations made on this basis agree very well with the observed values. The rate of penetration appears to be proportional to the concentration gradient of KG in the non-aqueous layer and in consequence depends upon the partition coefficients which determine this gradient. Exchange of ions (passing as such through the non-aqueous layer) does not seem to play an important rôle in the entrance of potassium. The kinetics of the model may be similar to that of living cells.     

A TECHNIQUE FOR THE ANALYSIS OF EPISTATIC GENE ACTION II. THE APPLICATION OF THE METHOD

With a method based on probability of phenotypic ratios being produced by crosses involving two pairs of interacting genes, data from genetic studies of Impatiens Sultana Hook. f. (Balsaminaceae) were analysed. Nine genes postulated to control floral color are: P, purple; I and W, white; R, red; O, orange; F, fuchsia; D, red; E, red; S, salmon. Epistatic action was evaluated, but progeny counts were too small for linkage to be determined.     

EXPERIMENTAL STUDIES OF THE EVOLUTIONARY SIGNIFICANCE OF SEXUAL REPRODUCTION. VI. A GREENHOUSE TEST OF THE SIB-COMPETITION HYPOTHESES

This study tests the hypothesis that competition among groups of sexual and asexual siblings generates an advantage for sexual females. Individual tillers of Anthoxanthum odoratum were planted singly, among other siblings from the same family, and among groups of sexual and asexual siblings from different families in pots in an unheated greenhouse. Unlike previous field experiments, there was little difference between the performance of sexual and clonal tillers after two years, despite strong treatment effects and high mortality. The results demonstrate that sib competition does not generate an advantage for sexual reproduction in biotically simple environments.     

A QUANTITATIVE ANALYSIS OF THE MEGAGAMETOPHYTE OF FIVE SPECIES OF CORNUS L.

Comparisons of variations of morphological features, treated quantitatively, of the megagametophytic stages in Cornus asperifolia Michaux., C. stricta Lam., C. amomum Miller, C. florida L., and C. alternifolia L. suggest differences in growth patterns of their megagametophytes. The successful application of the clearing fluid 41/2 (Herr Fluid) affords adequate data for assessment of quantitative features of such minute plants. This method, less time consuming than traditional paraffin sectioning techniques, allows for statistical treatment of a sufficient number of species for valid inferences of angiospermous embryological features. An investigation of megagametophytic size was directed both to successive stages within each species and to each stage among all five species. In both instances, means, confidence intervals (CI), and growth increments (GI) were compared. Without exception, the largest means for length and width occurred in the 8-nucleate stage for all species. The greatest GI for length occurred in the 8-nucleate stage for C. stricta, C. alternifolia, and C. asperifolia and in the 4-nucleate stage for C. florida. The 4- and 8-nucleate GI were nearly equal for C. amomum. Overlapping of 95 % CI between successive stages indicated uniform growth between stages for the megagametophyte. Only C. asperifolia had CI overlapping between all successive stages for length and width. These five species are clearly separated on the basis not only of variations in qualitative features but also on megagametophytic growth patterns among species.     

STUDIES ON THE REGULATION OF OSMOTIC PRESSURE : I. THE EFFECT OF INCREASING CONCENTRATIONS OF GELATIN ON THE CONDUCTIVITY OF A SODIUM CHLORIDE SOLUTION.

1. In pure gelatin solutions the conductivity of the solution increases with increasing concentrations, regardless of the hydrogen ion concentration. The actual value of the specific conductivity is greater at that reaction where the degree of ionization is greater. 2. The addition of gelatin in increasing concentrations to a 0.6 per cent sodium chloride solution affects the conductivity of that solution in two ways: (a) At pH 3.3, (where gelatin is highly ionized) the conductivity increases with each added increment of gelatin. (b) At pH 5.1 and 7.4 (where gelatin is less highly ionized) the conductivity decreases with each added increment of gelatin. A similar study is being made of crystalline egg albumin.     

A SPECIFIC CHECK LIST OF THE BIRDS OF GREECE.

This paper consists of a catalogue of all species known to occur in Greece. Indications are given of the status, distribution and relative abundance of all these (except rare vagrants and accidentals), in the north, centre and south of the country, and of the habitat or habitats in which they are generally found. The notes on each species are based on the studies mentioned in the list of references and on personal knowledge of the country gained during three years' residence from 1952–1955.     

A REVISION OF ARIOCARPUS (CACTACEAE). I. THE STATUS OF THE PROPOSED GENUS ROSEOCACTUS

Anderson, Edward F. (Claremont Graduate School, Claremont, California.) A revision of Ariocarpus (Cactaceae). I. The status of the proposed genus Roseocactus. Amer. Jour. Bot. 47(7) : 582–589. Illus. 1960.—The proposed genus Roseocactus Berger is found to be a subgenus of Ariocarpus. The subgenera Ariocarpus and Roseocactus are basically similar in habitat, seedlings, presence of mucilage systems, tubercle structure, seed structure, fruiting habit, flower origin and structure, alkaloidal properties, trichomes, pollen grains, and chromosome number. They differ in flower color, presence or absence of an areolar groove, tubercle divergence, and trichome texture. A hypothesis is proposed to explain variations in the areoles. The differences in structure of mature tubercles are thought to be due to variability in the location of growth and elongation with respect to the floral and spinous areolar areas.     

EXPERIMENTAL STUDIES OF THE EVOLUTIONARY SIGNIFICANCE OF SEXUAL REPRODUCTION. V. A FIELD TEST OF THE SIB-COMPETITION LOTTERY HYPOTHESIS

Sexually and asexually derived tillers of Anthoxanthum odoratum were planted directly in the field to test the hypothesis that competition among groups of sexual and asexual siblings favors the maintenance of sexual reproduction in populations. The results showed a substantial fitness advantage for sexual tillers. However, in contrast with the models, the advantage of sex did not increase with increasing numbers of colonists in the patch, there were multiple survivors among colonists, and an advantage was observed even for singly planted tillers. When a truncation-selection scheme was imposed ex post facto on the data, the relative performance of sexual tillers was similar to that predicted by the Bulmer (1980) model, suggesting that sib-competition models fail due to the violation of the assumption of truncation selection. The advantage of sex was not correlated with the presence of other species, total percentage cover, or species diversity, although sites where sex was favored were physically clustered.     

THE POTENTIAL AND RESPIRATION OF FROG SKIN : I. THE EFFECT OF THE HOMOLOGOUS CARBAMATES. II. THE EFFECT OF CERTAIN LYSINS

Measurements of the O₂ consumption and of the potential of frog skin, made under comparable conditions, show that the homologous carbamates (ethyl, propyl, butyl, and amyl) reduce both the O₂ consumption and the potential, but not in a similar manner. In this respect, the effect of the carbamates is like the effect of reduction in O₂ tension. The simple lysins (saponin and the bile salts), on the other hand, abolish the potential without reducing the O₂ consumption at all. Irrespective of whether one considers the concentration of carbamate in the entire system or the amount of carbamate adsorbed by the frog skin, Traube''s rule relating the effect of a carbamate to its position in the homologous series does not seem to apply.     

MORPHOLOGICAL STUDIES IN ALETRIS. I. DEVELOPMENT OF THE OVULE,MEGASPORES AND MEGAGAMETOPHYTE OF A. AUREA AND THEIR CONNECTION WITH THE SYSTEMATICS OF THE GENUS

Browne , Edward T., Jr . (U. of Kentucky, Lexington.) Morphological studies in Aletris. I. Development of the ovule, megaspores and megagametophyte of A. aurea and their connection with the systematics of the genus. Amer. Jour. Bot. 48(2): 143–147. Illus. 1961.—Development in a North American species of this variously classified genus has shown great similarity with the development in several genera of Hutchinson's Liliaceae-Narthecieae: Pleea, Tofieldia, Nanhecium and ∗∗∗Metaparthecium. The ovules are anatropous, bitegmic, crassinucellate and arranged in 4 rows in each locule of the tricarpellate pistil. There is a hypostase and an obturator. The primary archesporial cell is hypodermal. This undergoes a division to form a wall cell and the megaspore parent cell (MPC). The megaspores usually have a linear arrangement although occasionally a T-shaped tetrad may be formed. Most frequently the chalazal megaspore functions, but rarely the one adjacent to it may enlarge instead. Megagametophyte development is of the Polygonum type. A characteristic narrowed chalazal constriction is formed during the development of the megagametophyte. It is recommended on the basis of this information that Aletris be classified with the genera of the Liliaceae-Narthecieae.