240 ALLAN HAXCOCK PACIFIC EXPEDITIONS VOL, 20 



PLATE 12 



.Ircopsis solida (Sowerby) 1833. Bahia de Cartago, Albe- 

 marle Island, Galapagos Islands. Young specimen showing 

 sculpture similar to that of the genus Acar. Length, 5 mm. 

 Acar (jradata (Broderip and Sowerby) 1829. Isia Isabel, 

 Cjulf of California. Outside of right valve of young speci- 

 men. Coarsely sculptured form. Length, 10.2 mm. 

 Acar gradata (Broderip and Sowerby) 1829. Off Cabo de 

 San Francisco, Ecuador. Outside of right valve of young 

 specimen. Finely sculptured form. Length, 9 mm. 

 Acar pusilla (Sowerby) 1833. Isla La Plata, Ecuador. 

 Outside of left valve. Length, 7 mm. 



Acar hailyi Bartsch 1931. {forma insiilaris). Islas Secas, 

 Panama. Outside of left valve. Length, 10.2 mm. 

 Acar bailyi Bartsch 1931. {forma insularis). Islas Secas, 

 Panama, a. Dorsal view. b. Outside of right valve, c. Inside 

 of right valve, d. Outside of left valve, e. Inside of left 

 valve. Length, 9 mm. 



