UNIDENTIFIED LIMPETS. 159 



P. PURPURASCENS Anton. Oval, with 19 equal ribs, which 

 slightly project at the margin. Apex moderately high, blackish-red. 

 Apex and ribs yellow, showing on the inside. Length 11, breadth 

 9 lines. (Verzeich. p. 26.) 



P. CONICA Anton. Equals P. vulgata Lam., etc., the varieties 

 with equal broad and somewhat separated ribs and conic form. 

 Blainv. 49, 1 ; Mart. 1, 38. (Anton, Yerzeich. p. 26.) 



P. ALBESCENS Anton. Oval, nearly round, conical ; apex wart- 

 like, inclined forward. Very finely longitudinally, and still more 

 finely transversely striated. Yellowish-white ; inside pure white, 

 with a brown margin around the muscle-impression, below the mar- 

 gin horn-colored. Length 1, breadth 11 lines. Antilles. (Anton, 

 Verzeich. p. 26.) 



P. DICHOTOMA Anton. Oval, conical, white with brown longitu- 

 dinal lines, which below mostly divide gable-wise [y\ -shaped]. In- 

 terior whitish. Length 6, breadth 5? lines. Has the muscle-im- 

 pression of Patella and the outward aspect of Siphonaria. (Anton, 

 Verzeich. p. 26.) 



This may possibly be Acmwa cubensis Rve. (H. A. P.} 



P. (? TOREUMA, VAR.) TENuiLiRATA Carpenter. 



Shell much depressed, oblong, diaphanous ; corneous, irregularly 

 flamed with brownish-purple ; about 22 very delicate lirse, the inter- 

 stices obsoletely striated ; apex subprominent, situated about at the 

 front fifth. Interior very iridescent. Length 1*38, breadth 1, alt. 

 28 inch. (Opr.) 



Monterey (Hartweg) in Cuming Coll. 



This shell appears to agree with P. toreuma Reeve in all essential 

 respects ; but instead of the fine regular strise of that species, there 

 are a few delicate principal ribs, with obsolete strise between. As its 

 neighbor P. oregona sometimes developes large ribs, and is at other 

 times nearly smooth, this has not been considered a sufficient differ- 

 ence to constitute a species until more is known of its variable 

 powers. (Cpr. in P. Z. S. 1855, p. 233.) 



P. RUSTICA Linn. BORN has attempted the identification of this 

 perplexing limpet, his selection being perhaps the P. lusitanica. 

 His description is on p. 426 of the Mus. Cses., pi. 18, fig. 11. See 

 under P. lusitanica and P. neglecta, this volume. 



