EXPLANATION OF PLATE XXIV. 



Figure 137. — Littoriua ruclis, (p. 651 ;) natural size. 



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



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



140. — Littorinella 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. 656 ;) enlarged. 



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



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



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



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



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



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



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



153. — Ceritbiox)sis Greenii, (p. 647 ;) enlarged. 



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



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



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



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



158. — CiBCum pulcbellum, (p. 649;) natural size and enlarged. 



159. — Acmtea testudinalis, (p. 661 ;) natural size. 



159a. — The same ; lower side. 



159&. — The same, variety alveus ; natural size. 



(Figure 155 was drawn from nature, by A. E. Yerrill ; the otliers are from Biauey's Gould, mostly 

 drawn by E. S. Morse.) 



