Various

“ In this paper only the chief mass of the central nervous system is considered. The more evident parts of the central nervous system are arranged in general as in other forms. The circumoral nerves issue from under the lantern and run along the oral, cross over at the edge of the shell and then run along the aboral side. The five radial nerves converge at the five ocular areas near the center of the aboral region. The circumoral nerve ring is looped over and under parts of the lantern. Fig. 1 shows a part of the lantern and parts of three loops of the circumoral nerve trunk. ”

“ As a rule slightly larger cells are found near the nerve trunks and as some of these seem to send long branches out into the lateral trunks, they may be motor or sensory, the association neurones are probably the smaller cells in farther. The cells seem multipolar in most cases and in fact much more modified than the cells of starfish or sea-urchin. ”

“ The animals in the living condition are bright orange or red but lose their color very soon after preservation in alcohol or formalin.
The proboscis cavity extending the entire length of the organ is surrounded by a network of connective tissue supported by longitudinal bands of plain muscle. This cavity is supposed to communicate with the exterior by a very small opening, the proboscis pore, but this did not show in the specimens examined. The heart, proboscis gland and notochord are located in the posterior part of the proboscis. ”

“ The nerve trunks have about one to two layers of cells, the main part of the nerves are composed of longitudinal fibers. There are not so many evident vertical fibers from cells as found in starfish and some other forms. ”

“ By JAMES G. NEEDHAM, Ph.D., Professor of Limnology and General Biology in Cornell University, and JOHN T. LLOYD, A.B., Assistant in Limnology in Cornell University.
This book is a broad presentation of the field of fresh-water biology, primarily in its scientific aspects, also in its relation to commercial, civic, aesthetic and public health interests of man. There is no book in the English language covering the field. Copiously illustrated with photographs from Nature. ”

“ Special advantages are afforded by the fact that the college limits its attendance, the freshman class being restricted to two hundred applicants. The success of the college is particularly indicated by the large proportion of the graduates who proceed to advanced work in the large universities. ”

“ Nerve cells from central regions of a radial nerve. The arrangement is as shown in the drawing, cells of various levels shown as one layer. Some of the processes possibly relate nearby cells, but most fibers run into the general fibrous mass. All fibers or fibrils are small. There is some indication of tigroid substance in some of the cells. ”

“ The holes in the skeleton for the tube feet are shown as circles on each side of the diagram.
The general structure of the chief central nerve trunks is quite similar as shown in sections. Figs. 6, 7 and 8. ”

“ These muscle bands are probably used in altering the size and shape of the proboscis. Figs. 4, 20, 21.
The nervous tissue consists of many fibers thickly interwoven. There are a few small nuclei scattered about among the fibers. Figs. 12, 13.
The muscle is unstriated. The fibers are very long in some places, shorter in others and always quite distinct.
(Contribution from the Zoological Laboratory of Pomona College)
REFERENCES
[Pg 30]
EXPLANATION OF FIGURES
Fig. 1. Cross section through the gill region showing gill opening. D. N., dorsal nerve. D. V., Dorsal vessel. G. O., gill openings. ”