10 ACMJEA. 



WKINKAUFF (not Linne) Journ. de Conchyl. x, p. 334, 1862. 

 Patelloidea virginea COLBEAU, Moll. viv. de la Belg., p. 14. Patella 

 cequalis Sow., Min. Conch, t. 139. Patella astensis BONELLI. 



A small and delicate species, pink rayed on a pale ground. It is 

 widely distributed in European seas. The following mutations 

 have received names: 



Form cornea Jeffr. Smaller than the type, more conical, summit 

 more elevated, nearly central. This form is figured by Wood, 

 Crag Moll. pi. 18, f. 60. 



Form rotundata Monts. More rounded than the type. 



Form depressa Wood. Crag Moll. pi. 18, f. GA. 



Form unicolor Forbes. Of a uniform rosy color, without rays ; 

 small. 



Form lactea Jeffr. Milky-white. 



A. TESTUDINALIS Muller. PI. 9, figs. 25, 26, 27, 28, 29. 



Shell conical, oval, the apex a little in front of the middle ; pos- 

 terior slope slightly convex, other slopes straight ; surface more or 

 less distinctly, finely radiately striated ; color yellowish-gray, with 

 numerous blackish-brown stripes, generally broken into a coarse 

 network, or tessellated pattern. 



Inside white, with a large dark brown central area, the border 

 tessellated brown and white. Length 38, breadth 28, alt. 13 mill. 



North Atlantic and Arctic Oceans, southeast to the English Channel, 

 southwest to Long Island Sound; North Pacific from Sitka (and 

 Yesso f) to the Arctic Ocean. 



Patella testudinalis MULL., Prodr. Zool. Dan. p. 237, 1766. 

 REEVE, Conch. Icon. f. 70. Tectura testudinalis JEFFREYS, Brit. 

 Conch, iii, p. 246 ; v, p. 200, t. 58, f. 3. OLD., Invert, of Mass., 

 Binney's edit., p. 267, f. 529. Acmasa testudinalis FORBES & HAN- 

 LEY, Hist. Brit. Sh. ii,' p. 434, t. 62, f. 8, 9 ; t. AA, f. 2 (animal). 

 DALL., Amer. Journ. Conch, vi, p. 249, t. 14, f. 13 (dentition) ; 

 Proc. U. S. Nat. Mus. 1878, p. 339. SARS, Moll. Reg. Arct. Norv. 

 p. 120, t. ii. f. 9 (dentition). Lottia testudinalis FORBES, Malac. 

 Monensis p. 34. GLD., Invert, of Mass., 1st edit., p. 153, f. 12.- 

 Patella testudinaria and P. tessellata MULL. P. clealandi SOWB., 

 Trans. Linn. Soc. xi, p. 621. P. amcena SAY, Journ. Acad. N. S. 

 Phila. ii, p. 223. DE KAY, N. Y. Moll. p. 162, t. 9, f. 196. P. cly- 

 peus BROWN, 111. Conch. Gt. Br. t. 37, f. 9, 10. Patella alveus CON- 

 RAD, Journ. Acad. N. S. Phila. vi, p. 267, t. 11, f. 20, 1831. Patel- 



