MAZATLAN UNIVALVES aoe 
Famity CERITHIAD. 
Genus CERITHIUM, <Adans. 
Cerithium, Adanson, pars.—H. & A. Ad. Gen. vol. 1. p. 284.— 
Shell with short, scarcely recurved canal ; columella not 
plicated ; paries callous ; operculum Littorimoid, thick. 
381. CERITHIUM MACULOSUM, Kien. 
Kien. Icon. Conch. p. 36, no. 25, pl. 18, f. 3, (non 2.)—Lam. 
An. s. Vert. vol. ix. p. 312, no. 45.—Mke. in Zeit. f. Mal. 
1850, p. 178, no. 39.—(Non Vertagus maculosus, Martyn.) 
Cerithium adustum, (Aen. teste fig. non diagn.) C. B. Ad. 
Pan. Shells, p. 150, no. 193.—P. P. C. Cat. Prov. 
Cerithium nebulosum, Sow. Thes. Conch. sp. 71, pl. 179, f. 60. 
? + (var.) Cerithium adustum, Sov. loc. cit. sp. 70, pl. 178, f. 48.— 
(Non Kien. diagn. et f. 2.) 
Kiener accurately described the Mazatlan shell as C. macu- 
losum, but unfortunately in his plate named it C. adustum ; his 
diagnosis of that species (loc. cit. p. 37, no. 26, f. 2 non 3 ;— 
Lam. An. s. Vert. ix. p. 313, no. 46) being apparently intended 
for a Red Sea shell. Sowerby (following Desh. and Mike.) cor- 
rects the error of the plate, but alters both the species. He 
changes the name of this to C. nebulosum, because as he 
describes the whole family as one genus, he finds this term 
preoctupied: and he affiliates C. adustum to a Galapagos 
shell, which is probably only a smooth variety of the present 
species. The figure is indeed coloured orange brown; but 
that tint is not mentioned in the description, which accords 
sufficiently well with the Mazatlan shell. An analogous species 
is C. Guinaicum (Phil.) Sow. from Ld. Hood’s Island. 
The Mazatlan species has the first 8 whirls flat, with a 
divergence of 43°, and sculptured with about 15 very faint 
transverse ribs, crossed by about 5 rather strong lirule. Here 
and there a varix is formed. Afterwards the coste change 
into a row of stout tubercles, rather above the mi@dle of the 
whirls, sometimes with a few rows of smaller ones on the body 
and base of the shell. The spiral lirule become very faint, 
and are marked by lines of brown broken up into dots. Some- 
times there are large patches of blackish brown ; sometimes 
the prevailing hue is ight. The shell is generally very broad 
and gibbous; but sometimes it is elongated. The dwarf 
