Plate 20 

 PACIFIC COAST UNIVALVES 



a. ERODED PERIWINKLE, Littorina pla- 



naxis Phil., ^ inch (Washington to 

 Lower California), p. 134. 



b. SITKA PERIWINKLE, Littorina sitkana 



Phil., % inch (Alaska to Washington), 

 p. 134. 



c. CHECKERED PERIWINKLE, Littorina 



scutulata Old., Yj inch (Alaska to 

 Mexico), p. 134. 



d. FLAT WORM-SHELL, Spiroglyphus 



lituellus Morch (Alaska to California), 

 p. 144. 



e. SCALED WORM-SHELL, Aletes squami- 



geriis Cpr. (Alaska to Peru), p. 144. 



f. ONYX SLIPPER-SHELL, Crepidula ojiyx 



Shy., 2 inches. Left shell lived on 

 scallop (California to Chili), p. 171. 



g. COOPER'S TURRET-SHELL, Turritella 



cooperi Cpr., 2 inches (California to 

 Mexico), p. 141. 



h. MARIA'S TURRET-SHELL, Turritella 

 mariana Dall, 2^ inches (California to 

 Panama), p. 142. 



i. RECLUZ'S MOON-SHELL, Polinices reclii- 

 sianus Desh., 2 inches (California to 

 Lower California), p. 187. 



j. WROBLEWSKI'S WENTLETRAP, Opalia 

 wrobleivshii Morch, 1 inch (Alaska to 

 San Diego, California), p. 162. 



k. PACIFIC HALF-SLIPPER SHELL, Crepi- 

 patella lingulata Gld., % inch (Alaska 

 to Panama), p. 170. 



1. PACIFIC CHINESE HAT, Calyptraea 

 fastigata Gld., 1 inch (Alaska to Cali- 

 fornia), p. 169. 



m. GOULD'S DOVE-SHELL, Nitidella goiildi 

 Cpr., Yi inch (Alaska to California), 

 p. 222. 



n. PACIFIC MUD NASSA, Nassarius tegula 

 Reeve, % inch (California to Lower 

 California), p. 238. 



o. APPLE SEED, Erato vitellina Hinds, Yi 

 inch (California to Lower California), 

 p. 176. 



p. IDA'S MITER, Mitra idae Melville, 2 

 inches (California), p. 249. 



q. BEATIC DWARF OLIVE, OUveUa beatica 

 Cpr., Y inch (Alaska to California), 

 p. 247. 



r. CALIFORNIAN FROG-SHELL, Bursa 

 californica Hinds, 4 inches, with cluster 

 of eggs laid on clam shell (California 

 to Lower California), p. 199. 



s. GIANT WESTERN NASSA, Nassarius 

 fossatus Gould, 2 inches (Vancouver, 

 B. C, to Lower California), p. 240. 



t. Top view of living animal of Oliva, p. 245. 



u. SOLANDER'S TRIVIA, Trixna solandri 

 Sby., % inch (Catalina Island, Cali- 

 fornia to Panama), p. 179. 



v. CALIFORNIAN TRIVIA, Trivia califor- 

 niana Gray, '2 inch (California to 

 Mexico), p. 179. 



w. X-ray photo of SPINDLE SHELL, Fusinus, 

 p. 243. 



