GASTEROPODA. 



113 



No. 274. Pyrula (Tudicea) rusticula, Bast. 



Miocene, Grund, Hanover. 



No. 275. Natica sigaretina, Desh. 



Tliis genus of predaceous blind moUusks, with subglobular shells, has had 

 a world-wide distribution since the Silurian, 500 being fossil and 200 living. 

 Family Naticid*. Eocene, Paris basin, France. 



No. 276. Natica millepunctata, Lam. 



Quaternary, Palermo, Sicily. 



No. 277. Natica helicina, Broc. 

 Miocene, Soos, Austria. 



No. 278. . Crepidula cornu-arietes. 



A septum covers the posterior half of the interior of the shell in this genus, 

 which is widely distributed now, living since the Cretaceous. Family Calyp- 

 teidse. Eocene (Claiborne Epoch), Claiborne, Alabama. 



No. 279. Xenophora crispa, Chem. 



The genus, found fossil since the Devonian, is small to-day. 

 the family Onustidoe. Quaternary, Mt. Pelegrini, Sicily. 



It belongs to 



No. 280. [622, Cast]. Euomphalus pentangulatus, Sow. 



This genus, now entirely extinct, was present in con- 

 siderable numbers in the Palseozoic seas, from the Lower 

 Silurian to the Trias. Its discoidal form, angular whorls, 

 and large umbilicus, make it a shell easil}^ recognizable, 

 and a serviceable fossil in the determination of the age 

 •of strata in which it occurs. This specimen is from the 

 Carboniferous Limestone of Kildare, Ireland. 



No. 281. Raphistoma lenticulare, Sow. 

 Trenton Limestone, Jefferson Co., New York. 



No. 282. Opalia varicostata, Stearns. 

 Tertiary, San Diego, California. 



No. 283. Opalia anomala, Stearns. 

 Tertiary, San Diego, California. 



No. 284. Turritella turris, Bast. 



The family Turritellidae dates from the Triassic, and this type 

 genus has the same range. 

 Miocene, Grund, Hanover. 



