MAZATLAN UNIVALVES 461 
Genus STRIGATELLA, Swains. 
Treatise, &c. 1840. 
Mitra, pars, auct. Shell Collumbelloid. 
586. STRIGATELLA TRISTIS, Brod. 
Mitra tristis, Brod. Proc. Zool. Soc. 1835, p. 194.—Rve. Conch, 
Ic. pl. 15, f. 114.—C. B. Ad. Pan. Shells, p. 44, no. 20. 
Strigatella tristis, H. f A. Ad. Gen. i. 174. 
= Mitra amphorella, P. P. C. Cat. Prov. non Lam. 
There are 4 distinct columellar plaits, with one rudimentary 
in the adult. In very young shells, only three are seen. There 
is no sculpture except some faint spiral lines, and very irregu- 
lar swellings of growth. The shoulder is more or less swollen, 
with a light band more or less developed. The largest speci- 
men measures long. 1°2, long. spir. ‘47, lat. °58, div. 50°. 
An acuminate sp. ,, “y); 3 TASC $i) 305d) ae 
A broad sp, DH iene 58 i SBA fyi ADs: aig OOK 
Hab—St. Elena and Galapagos ; in sandy mud, 6—10 fm. ; 
Cuming.— Panama; very rare, under stones near low water 
mark; C. B. Adams.—Mazatlan ; not uncommon, generally 
incrusted ; L’pool Col. ~ 
Tablet 2100 contains 3 sp. very acuminate.—2101, 4 do. spire 
elevated.—2102, 5 do. normal state.—2103, 4 do. broad form.— 
2104, 2 sp. after acid, shewing colour.— 2105, 2 sp. much 
encrusted with coralline and Bryozoa.—2106, 3 sp. mended 
after fracture. 
Famitry MARGINELLIDZ. 
587.. MarGINnELLA MINOR, C. B. Ad. 
Pan. Shells, pp. 40, 304, no. 40. 
Gibberula (Persicula) minor, H. & A. Ad. Gen. i. 193. 
This species is stated by Prof. Adams tobe the analogue of 
the W. Indian M. Lavalleana, D’ Orb. B. M. Cat. Cub. Moll. 
p. 25, no. 282, (=M. minima, Guild.) from which it differs in 
being narrower at.the shoulder. About 200 specimens were 
found on shells, but mostly young or imperfect. It is extremely 
glossy, never horn-coloured when fresh, white, nearly trans- 
parent, in shape somewhat like M. sapotilla; with two pro- 
