_Seila assimilata_ Cpr. Dark brown. Pl. V. Fig. 4 ×6. _Turbonilla lammata_ Cpr. Pl. IV. Fig. 4 ×10. Light brown. (Dunkeria). _Tinostoma supravalata_ Cpr. (?). Pl. V. Fig. 5 ×6. Clear white. (Ethalia). _Callistoma tricolor_ Gabb. Pl. V. Fig. 5 ×10. _Phasianella pulloides_ Gld. Pl. V. Fig. 6 ×6. Mottled red and white. _Tritonalia barberensis_ Gabb. Pl. V. Fig. 7. _Leptothyra baccula_ Cpr. Pink to gray. Pl. V. Fig. 8 ×6. _Leptothyra carpenteriana_ Pilsb. Red Turban-shell. Pl. V. Fig. 9 ×6. _Leptothyra paucicosta_ Dall. White. Pl. V. Fig. 10 ×6. _Jeffreysia translucens_ Cpr. (?). Pl. V. Fig. 11 ×6. _Pedipes unisulcata_ J. G. Cooper. Light brown. Pl. V. Fig. 12 ×6. _Mitromorpha aspera_ Cpr. Brown. Pl. V. Fig. 13 ×6. _Vermetus anellum_ Morch. White. Pl. IV. Fig. 6 ×10. This specimen is more coiled than some others. _Cerithiopus convexa_ Cpr. Dark brown. Pl. V. Fig. 14. _Cerithiopus columna_ Cpr. Light brown. Pl. V. Fig. 15. _Turritella mesalia lacteola_ Cpr. Pure white. (No figure.) _Bithium aspera_ Gabb. Brown. Pl. IV. Fig. 7 ×10. _Turbonilla stylina_ Cpr. (?). Pl. IV. Fig. 8 ×10. _Turbonilla costanea_ Cpr. (?). Pl. IV. Fig. 9 ×10. _Anachis subturiata_ Cpr. (?). Pl. IV. Fig. 10 ×10. _Amphissa versicolor_ Dall. Pink, white, brown. Pl. V. Fig. 16 ×6. _Corbila luteola_ Cpr. Small bivalve. _Philobrya setosa_ Cpr. Small bivalve. Pl. V. Fig. 17 ×6. _Acila castrensis_ Hds. Brownish. Pl. V. Fig. 18 ×6. _Carditanera minima_ Dall. Brownish-yellow. Pl. IV. Fig. 11 ×10. _Crassatella marginata_ Cpr. Pl. IV. Fig. 12 ×10. _Lasea rubra_ Mort. Tinged with red. Pl. V. Fig. 19 ×10. _Arca solida_ Br. & Sby. (?). Pl. V. Fig. 20 ×10. (_Contribution from the Zoological Laboratory of Pomona College_) [Illustration: Plate I] [Illustration: Plate II] [Illustration: Plate III] [Illustration: Plate IV] [Illustration: Plate V] A Reconstruction of the Nervous System of a Nemertian Worm WILLIAM A. HILTON Small specimens of _Carinella cingulata_ Cole were fixed in Mercuric chloride and cut in series. A general hematoxylin stain was very satisfactory for general anatomy. For a study of the finer structure other preparations will be necessary. No attempt will be made to give a complete review of the literature relating to this group. Almost every systematic paper has something, because of the importance of the nervous system in classification and because in many cases the nervous system may be seen through the body-wall without dissection.