504 PR0CEEDIN08 OF THE NATIONAL MUSEUM. vol.45. 



Verrill, a. E. — Continued. 



1872. Recent additions to the molluscan fauna of New England. Amer. Joirrn. 



Sci., ser. 3, vol. 3. 

 1879. MoUuscoids in: Contributions to the IJIatural History of Arctic America, 

 made in connection with the Howgate Polar Expedition, 1877-78. 

 Bull. U. S. Nat. Mus., No. 15, p. 147. 

 Wagner, N. 



1885. Die Wirbellosen des Weissen Meeres, Leipzig. 



EXPLANATION OF PLATES. 



Plate 33. 



Fig. 1. View of left side of Eugyrioides dalli, test removed. The first bend of the 

 intestine is more open in the specimen figured than is typical. X 1. &• s., 

 branchial siphon; int., intestine; ov., ovary; st., stomach; tes., testis. 



2. A tentacle of E. dalli. b. t., branchial tentacle. 



3. Branchial sac of E. dalli, inner surface, i. I. v., internal longitudinal vessels; 



s., stigmata; t. v., transverse vessel. , 



4. Halocynihia washingtonia, surface view, left side. X 1. a. s., atrial siphon. 



5. Orifices of H. washingtonia. a. s., atrial siphon; h. s., branchial siphon. 



6. Esophagus, stomach, and "liver" of H. washingtonia, showing wide separation 



of the parts of the liver, es., esophagus; I., liver; V., secondary liver; st., 

 stomach. 



7. nalocynthia haiistor foliacea. X a. s., atrial siphon; b. s., branchial siphon. 



8. Hartmeyeria triangularis. X 2/3. b. s., branchial siphon; ped., peduncle. 



9. H. triangularis, test removed to show particularly the arrangement of the 



muscle bands of the mantle, b. s., branchial siphon; int., intestine; m.f., 

 muscle fibers; ov., ovary. 



10. H. triangularis, left side, mantle with adhering alimentary and reproductive 



systems dissected and turned back to expose the inner face of these and the 

 outer face of the branchial sac. b. s., branchial siphon; b. sc, branchial 

 sac; gon., gonad; int., intestine; I., liver. 



11. H. triangularis, b. t. branchial tentacles; ef, ef the unique epithelial folds; 



gn. ganglion; hy, the hypophysis; pg-pg\ peripharyngeal groove. 



12. Atrial tentacles and periatrial fold, E. triangularis, a. t., atrial tentacle; 



p. a.f., periatrial fold. 



13. Branchial membrane of H. triangularis, b. /., branchial fold; d. I., dorsal 



lamina; t. v., transverse vessel. 



Plate 34. 



Fig. 14. Culeolussluiteri, Buriaceyiew. XL 6. s., branchial siphon; pe<?., peduncle. 



15. Tentacle of C. sluiteri. b. t., branchial tentacle. 



16, 17. Gonads, right and left side respectively, of C. sluiteri. int., intestine, 



ov., ovary; tes., testis. 



18. Styela macrenteron. A small short individual, with a prominent inter- 



siphonal horn. X 2/3. b. s., branchial siphon. 



19. S. macrenteron. An elongate individual, mantle of left side thrown back to 



expose the reproductive and alimentary systems. X 2/3. o v., ovary; v., 

 rectum; tes., testis. 



20. The intestinal tract of S.. macrenteron at its extreme of length and coiling. 



X 1. an., anus; int., intestine; r., rectum; St., stomach. 



21. 22. Styela hemicasspitosa, "high" and "low" forms, respectively. X li- 

 23. Alimentary and reproductive systems of S. hemicsespitosa and their relation 



to each other, ov., ovary; tes., testis. 



