ACM^EA. 31 



1855 Collisella pediculus DALL, Amer. Journ. Conch, v i. p. 255, 

 t. 15, f. 16 (dentition). 



The ribs extend to the margin in this species ; in A. discors they 

 merely pucker the central part. Some specimens have the interior 

 most beautifully variegated with rich brown, black and steel-blue. 

 One of these, from the Academy collection is figured on pi. 7, fig- 

 ures 68-70. The figures on pi. 6 represent Reeves synonymous P. 

 corrugata. 



A. STIPULATA Reeve. PI. 6, figs. 27-31. 



Shell solid, ovate-oblong, depressed, apex in front of the middle ; 

 slopes convex ; sculptured with about 10 principal radiating ribs, 

 scarcely larger than the numerous wide and narrow, rounded inter- 

 mediate ribs, but giving a somewhat angular outline to the base. 

 Color " greenish-black, faintly rayed with a few whitish lines " or 

 light green, blotched with dark olive. 



Inside white tinged with green, muscle-scar impressed, narrow, 

 white, the tract within it olive-green ; border of shell light green, 

 clouded with blue-green and irregularly dotted with black. 



Length 27, breadth 18, alt. 6 mill. 



Panama. 



P. stipulata Rv., Conch. Icon. f. 117,- 1855. 



A solid, depressed species, with low, rounded ribs, the interior 

 having an olive or brownish-green central area. A specimen in the 

 collection of the Smithsonian Institution agrees with the one figured 

 from the Philadelphia collection (figs. 29, 30, 31). The other fig- 

 ures, 27, 28, are from Reeve, and represent a slightly different 

 coloring. 



Undetermined West American species of Acmcea. 



Patella (Acmcea f ) personoides Midd., Beitr. zu einer Mai. Rossica 

 ii, p. 37, t. 1, f. 2, (=A. ancyloides Midd., Bull Acad. Sci. St. Petersb. 

 vi) from Kenai Bay, north-west Coast America, is probably a form 

 of A. pelta Esch. 



Patella (Acmcea /) ceruginosa Midd., I. c., p. 38, 1. 1, f. 1, is perhaps 

 a form of A. patina. 



Lepeta puntarencK Morch (Mai. Bl. vii, p. 175) is perhaps an 

 Acmcea. The description is as follows : Shell oval, apex eleVated, 

 excentric ; inside milk-white, outside yellowish, closely decussated 



