The chromosomes of a long-isolated monotypic butterfly genus: Tellervo zoilus (Nymphalidae: Ithomiinae) in Australia

The chromosome number of the Australian butterfly Tellervo zoilus, the only representative of the subfamily Ithomiinae outside tropical America, is reported as n = 32. The meiotic metaphase chromosomes and adults of the typical subspecies are illustrated, and the significance of this particular chromosome number is discussed.     

Cavity-dwelling organisms in Lower Cambrian patch reefs from southern Labrador

An intact and well-preserved biota of cavity-dwelling organisms (coelobionts) of early Cambrian age is found within growth-framework cavities in archaeocyathid patch reefs of the lower Forteau Formation (upper Bonnia-Olenellus Zone) of southern Labrador. The biota was diverse, and consisted of encrusting and vagrant organisms. Renalcis , a Renalcis-like form, Epiphyton, Girvanella , and Serligia , all lived attached to walls and roofs of the cavities; other attached forms were Bija, Archaeotrypa , and two types of Wetheredella , an agglutinated foraminifer. Other organisms, including trilobites, probable calcareous ostracodes, brachiopods, echinoderms, and worms, as well as fungi, are also found preserved within the cavities. The structure of the coelobiontic community is surprisingly modern; it indicates that as early as the Lower Cambrian coelobiontic organisms were well-established in reefs, and were an important part of the reef community as a whole.     

A New Method for the Isolation of Etioplasts with Intact Envelopes

Electron micrographs are presented to demonstrate a new methodfor the isolation of etioplasts with intact envelopes developedafter comparing the known methods of isolation including thoseusing zonal centrifugation. This new method employs a columnof Sephadex G-50 (coarse) as one of the separation stages.     

Depression of Humoral Antibody Formation in the Chicken by Thymectomy and Antilymphocyte Serum

STUDIES on the chicken¹ established that transplantation immunity and humoral antibody formation were two independent systems of immune reactivity which were under the developmental control of two distinct primary lymphoid organs—the thymus and the bursa of Fabricius. Although a clear distinction of the two primary lymphoid organs has not been made in mammals, a division between thymus-dependent (T cells) and thymus independent (B cells) lymphocyte functions is now well documented^2,3. In the mouse, T cells are involved in cell mediated immune responses and are also necessary for the full expression of the humoral antibody response to many antigens.     

Kinetosome Production in Condylostoma Occurs During Cell Division*

Kinetosome counts in different stages of the cell cycle of Condylostoma indicate that somatic kinetosome production occurs during cell division. The kineties apparently increase in length during interphase by spacing-out of preexisting kinetosomes. This spacing-out may be passive and caused by expansion of the cortical membrane to which the kinetosomes are attached.