MAZATLAir UNIVALVES 



271 



A loug decked sp., margin to front "36, to hack '47. 

 A short do. ,, "48, „ '3. 



Hah.—{G. aculeata) W. Indies, passim, az^cf .— Cuba, Sagra.— 

 Honduras, Dyson. — Brazils: Patagonia; D'Orhigny. — Ben- 

 guela ; 1 sp. in excellent preservation ; Tarns. — Table Bay, 

 Krauss.—Czi-\}e Natal, Mus. Cuming.— Isle of France, Fav- 

 a/me.— Kurachee, Movith of the Indus, Mus. Cuming.— Port 

 Jackson, Eev. R. L. King.— 'New Zealand, Bev. B. Taylor.— 

 Sydne.y and Swan Eiver, Mus. Cuming.— (Dark var.) Japan, 

 Mus. Cuming.— (Light var.) Chili, Ca2}t. Ld. Byron. — (C. 

 echinus, &c.) Lobos Is. Pervi, Cuming. — Panama; under stones 

 at low water, rare ; C. B. Adams.— (G. Californica) Monterey, 

 common, Nuttall. — Mazatlan ; common, on shells &c. ; 

 young shells abundant on Chamge and Spondyli ; L'pool Col. 

 Tablet 1321 contains 10 sp. extremely young.— 1322, 7 do. a 

 stage older, with a fragment to shew the inner surface of the 

 deck.— 1323, a young deformed shell, nearly smooth, probably 

 belonging to this species. 



Specimens illustrating fo^'m and scidpture. — Tablet 1324 con- 

 tains 8 sp. [var. hystrix) of different ages. — 1325, 13 sp. do. 

 (var. echinus.)- 1326, 8 sp. do. finely aculeate, arched. — 1327, 

 10 sp. do. flat, (one of the young in situ on an adult.) — 1328, 8 

 sp. do. spiny processes 'imperfectly developed. — 1329, 4 sp. do. 

 {var. Californica.)— 1330, a series of 12 sp. shewing gradations 

 between the above forms. — 1331, 7 sp. shewing gradations from 

 flat to arched. — 1332, 6 sp. shewing gradations in amount of 

 spiral involution.— 1333, 5 sp. shewing gradations in size of 

 deck. — 1334, 6 sp. shewing gradations in prominence or sinking 

 of deck. 



Specimens shelving shape of deck. — Tablet 1335 contains 3 sp. 

 center pointed, sides much swoUen. — 1336, 4 do. sides swoUen. 

 — 1337, 3 do. sides slightly swoUen. — 1338, 3 do. center 

 rounded. — 1339, 1 do. point tiu-ned outwards. — 13 J/3, 4 do. form 

 approaching C. nivea. — 1341, 3 do. deck partially opaque. 



Specimens displaying changes of colour. — Tablet 1342 contains 

 2 sp. (hystrix and echinus) pure white. — 1343, 10 sp. variously 

 shading into brown. — 1344, 11 sp. do. dark lustrous brown. — 

 1345, 12 sp. tortoiseshell, variously mottled. — 1346, 5 do. whiter 

 tint. — 1347, 6 do. more or less tinged with green. 



Distorted specimens. — Tablet 1348 contains 7 sp. of irregular 

 shape. — 1349, 7 sp. diseased by worms. — 1350, 3 sp. with addi- 

 tional margin. — 1351, 4 sp. passing towards C. nivea.— 1352, 3 

 sp. passing towards C. onyx. 



