The surface epithelium is modified ciliated columnar, varying slightly in thickness, size of nuclei and size and shape of cell according to location. Figs. 13, 14, 15. The epithelium forming the gills and intestine is also modified ciliated columnar. That of the gills having short narrow cells and small nuclei, and that of the intestine having longer thicker cells and large nuclei. Figs. 11, 10. The connective tissue surrounding the proboscis cavity is of a peculiar arrangement. The connective tissue itself consists of fine strands loosely interwoven, but arranged in a definite manner. The strands form a fine network which gives a beautiful lacy appearance. Small round nuclei are quite numerous in connection with the strands. Longitudinal bands of plain muscle are very conspicuous in the connective tissue. 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 _Assheton, Richard_ 1918 A new species of Dolichoglossus. Zool. Anz. Bd. 33, p. 517-520. _Delage and Herouard_ 1898 Traite De Zoologie concrete Vol. 8. Les Procordes. Balanoglossus. Encyclopedia Britainica Balanoglossus. _Shipley, Arthur E._ 1893 Zoology of the Invertebrata. Balanoglossus. 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. A, alimentary corps. G., gill. V. N., ventral nerve. V. V. ventral vessel. N., nervous tissue. x40. Fig. 2. Cross section through the base of the proboscis showing diverticulum wall and proboscis gland. D., diverticulum. N., nervous tissue. P. G., proboscis gland. x40. Fig. 3. Longitudinal section through a gill opening. N., nervous tissue. G., gill. G. O., gill opening. x40. Fig. 4. Cross section through the center of the proboscis. N., nervous tissue. M. C., muscle in the connective tissue. T., connective tissue. x90. Fig. 5. Longitudinal section through the base of the proboscis and collar. M., mouth. C. N., central nervous system. H., heart. No., notochord. P. G., proboscis gland. N., nervous network. A., alimentary canal. D. V., dorsal ventral. x40. Fig. 6. Cross section through the base of the proboscis showing thickened nerve network. N., nerve network. D., diverticulum wall. H., heart. x40. Fig. 7. Cross section through gill region. D. N., dorsal nerve. D. B. V., dorsal blood vessel. G. B., gill vessel. V. N., ventral nerve. V. V., ventral vessel. x40.