202 MAZATLA3S' TTNIVALTES 



distinct radiatiug black lines. Sometimes tlie internal sui-face 

 is beaiitifiilly mottled -n-itli pnrple or brown. The animal 

 mark is by no means constant in shape ; but, when well defined, 

 shews the body gathered pretty regularly into points with 

 curves between. The smallest specimen is about '25 in length ; 

 the largest measures long. 2'15, lat. 1"7, alt. '72 



.SffS.— Mazatlan, Lieut Shplei/.—S. ^Y. Mexico, P. P. C— 

 Mazatlan verj' common ; L'i)ool ^' Havre Coll. 



Tablet 923 contains 4 sp. various ages. — 924, 4 specimens 

 white. — 925, 5 do. greenish tinge. — 926, 4 do. coloured within. — 

 927, 4 do. tortoiseshell.— 928, 8 sp. yellowish tinge.— 929, 4 do. 

 very faint appearance Of marginal dots. — 930, 7 do. a shade 

 more developed. — 931, 8 sp. black rays coated over. — 932, 7 sp. 

 black dots distinct. — 933, 7 do. more distinct. — 934, 7 do. well 

 developed. — 935, 5 sp. faint black dotted margin. — 936, 5 do. 

 distinct black margin.— 937, 6 sp. with brown tortoiseshell 

 markings. — 938, 5 do. piirplish tinge. — 939, 4 do. black and 

 brown. — 940, 3 sp. body mark distinct. — 941, 3 sp. margin 

 abnormally indented. — 942, 5 sp. irregidar internal growth. — 

 943, 1 do. -with large Balanus, Lithophagus, &c. 



GEurs NACELLA, Schum. 

 Patella, pars, atict. 



262. Nacella, , s}). ind. 



Tablet 944 contains a solitary specimen of a Nacella, of the 

 shape and size of Ancylus fluviatilis, with the apex spirally 

 recurved, and of a dark hornj- coloiu'. It is not perfect enough 

 for description. 

 Hah. — Mazatlan ; off Chama, 1 sp. : L'pool Col. 



Family ACM^ID.E. 



Genus ACMJi^A, Esch. 



EschschoUz Z»ol. All. ed. Rathlce, 1833, p. 16, (di,agnosi copiosa.) 



—Forhes Sf Hani. Br. Moll. vol. ii. p. 434.— TFooc/w. Man. 



Moll. p. loo.— Phil. Handh. Conch, p. 199. (Non Acme, 



Hartm. 1821.) 

 Lottia. G-rai/ in Fhil. Trans. 1833, and in Sow. Gen. 1833. 

 Patelloida, Quoi/ Sf Gaim. 1834, Voy. Astr. vol. iii. p. 349. 

 Tectiu'a, Audouiti Sf Milne Edw. Ann. Sc. Nat. 1830, vol. xxi. 



p. 226, (Gray: p. 325, Phil.J—H. Sf A. Ad. Gen. vol. i. p. 458. 



