EXPLANATION OF PLATE XXIV. 



Figure 137. — Littoriua riulis, (p. G51 ;) natural size. 



138. — Littoriua palliata, (p. 652;) natural size. 



139. — Lacuna vincta, (p. 652 ;) eularsetl. 



140.— Littoriaella minuta, (p. 653;) enlarged. 



141. — Eissoa aculeus, (p. 654 ;) enlarged. 



142. — Skenea planorbis, (p. 655 ;) enlarged. 



143.— Odostomia producta, (p. 656;) enlarged. 



144. — O. fusca, (p. 656 ;) enlarged. 



145.— O. trifida, (p. 6.56 ;) enlarged. 



146.— O. tritida, var., (p. 656 ;) enlarged. 



147. — O. impressa, (p. 656 ;) enlarged. 



148. — O. seminuda, (p. 657 ;) enlarged. 



149. — Eulima oleacea, (p. 655;) natural size. 



150. — Ceritliiopsis terebralis, (p. 648;) enlarged. 



151. — C. Emersonii, (p. 648;) enlarged. 



152. — Triforis nigrocinctus, (p. 648 ;) enlarged. 



153. — Ceritliiopsis Greenii, (p. 647 ;) enlai'ged. 



154. — Bittiuui nigrum, (p. 648;) enlarged. 



155. — Turbonilla elegaus, (p. 657 ;) much enlarged. 



156. — Margarita obscura, (p. 661 ;) natural size. 



157. — Vernietus radicula, (p. 649 ;) natural size. 



158. — Ca>cum pulcliellum, (p. 649;) natural size and enlarged. 



159. — Acma;a tostudinalis, (p. 661 ;) natural size. 



159«. — The same ; lower side. 



159Z>. — The same, variety alveus; natural size. 



(Figure 155 was drawn from nature, bj- A. E. Verrill ; the otlicrs are I'loui Binasy's Gould, mostly 

 drawn by E. S. Morse.) 



