ACM^A. 15 



of brown (not striped as in pelta and persona) between the principal 

 ribs, which delicately dot the otherwise uniform white margin. 

 Sometimes the principal ribs are rather sharp, palmating the margin, 

 occasionally they are small and crowded, becoming faint at the mar- 

 gin, when the shell presents the internal aspect of A. mitella; at 

 other times assuming that of Patella pediculus.. Generally the apex 

 is at the anterior third ; rarely at the anterior fourth, with very 

 elongated outline ; but sometimes is nearly central, with a rounded 

 shell. In this species also there is occasionally found a var. iextilis; 

 when the ribs become faint and distant, the color-lines run into net- 

 work, and the shell is of a thinner texture. The young is extremely 

 inequilateral, and rapidly developes the characteristic ribs. Inside 

 the shell has a white callus, through which the dark irregular blotch 

 appears. This occasionally takes the form of irregular ghostly bars, 

 which gave the name to the species. ( Cpr.) 

 Length 34, breadth 24, alt. 12 mill. 



Bodega Bay and San Francisco south to Lower California. 



Patella spectrum Rv., Conch. Icon. f. 76. Acmcea spectrum CPU., 

 Amer. Journ. Conch, ii, p. 339. Collisella spectrum DALL, Amer. 

 Journ. Conch, vi, p. 251, t. 14, f. 10 (dentition). Lottia scabra 

 GLD. (part), Expl. Exped. Shells. 



The very strong ribs of the outside, and the curiously marked 

 interior, like print of a hand, are prominent characters of this 

 species. 



It belongs to a group of forms represented in South America by 

 A. variabilis and A. ceciliana; in China by A. hieroglyphica, and 

 in Australasia by A. marmorata, etc. All showing curiously figured 

 interiors. 



A. PERSONA Eschscholtz. PL 2, figs. 25, 26, 27, 28 ; pi. 3, figs. 51-56. 



Shell oval, apex pointing forward, posterior slope long, convex, 

 anterior slope short. Sculptured with strong, rounded ribs, .usually 

 nodulous, but sometimes obsolete. Whitish, with stripes and zigzags 

 of blackish-brown, or olive-green variegated and speckled with 

 white. Margin crenated by the ribs. 



Inside white or stained with yellowish-brown, with a large central 

 deep brown area, rarely absent ; border articulated black and gray 



Sitka to Turtle Bay, L. California. 



A. persona ESCH., Zool. Atl. v, p. 20. no. 9, t. 24, f. 1, 2. CPR., 

 Amer. Journ. Conch, ii, p. 337. A. ancylus ESCH., I. c., t. 24, f. 



