MAZATLAN UNIVALVES 403 
This shell may be the C. achatinus of Menke, instead of the 
next Pspecies. It is closely allied to that and several other 
forms. The epidermis, when very fresh, is thin, dark olive, 
with more or less conspicuous scaly ridges of growth, crossed 
by spiral lines of short bristles, of which one is conspicuous on 
the shoulder; in the sinus area, imbricated. A swollen sp. 
measures long. 2°18, long. spir. °33, lat. 1°37, div. 110°. 
An elongated sp. ,, 2°07, ¥ coo eee te Oye. caer bees 
Hab.—Is. Annaa, Sowerby. [?]—Panama; in sandy mud in 
clefts of rocks; Cuming.—Do.; 12 sp. under stones, at ex- 
treme low water mark; C. B. Adams.—San Blas, Hinds.— 
Mazatlan ; extremely rare; L’pool Col. 
Tablet 1923 contains 3 sp, somewhat varying.—1924, 3 sp. 
approaching C. regalitatis. 
477. CONUS REGALITATIS, Sow. 
Proc. Zool. Soc. 1834, p. 19.— Mill. Syn. Nov. Test. Viv. 
p. 124.—Sow. Conch. Ill. pl. 57, f. 87.— Rve. Conch. Lil. pl. 40, 
f. 218.—Lam. An. s. Vert. vol. xi. p. 133, no. 192.—Kien. 
Icon. Conch. p. 237, pl. 39, f. 3—C@. B. Ad. Pan. Shells, 
p. 109, no. 119. 
P=C. achatinus, Mike. in Zeit. f. Mal. 1847, p. 183, no. 23.* 
(non Brug.) 
Chelyconus (Leptoconus) regalitatis, H. §& A. Ad. Gen. i. 254. 
PAn C, purpurascens, var. 
The few specimens belonging to this form were soon caught 
up by collectors. It is distinguished by the shape and paint- 
ing; but the Mazatlan specimens were not so constant in 
these respects as to have authorized the separation. At the 
same time they were not numerous enough to warrant me in 
uniting what those who have paid particular attention to the 
tribe have had grounds for separating. Epidermis generally 
smoother than in C. purpurascens. Long. 2'1, long. spir. °37, 
lat. 1°1, div. 11°. 
Hab.—Real Llejos ; in clefts of rocks on sandy mud ; Cuming. 
—Panama; 9 sp. under stones at extreme low water, (one 
measuring 3°); C. B. Adams.—S. W. Mexico, P. P. C.— 
Mazatlan ; extremely rare; L’pool Col. 
Tablet 1925 contains the finest specimen. 
* Dr. Menke also quotes in his list the well known C, omaria, Zeit. f. Mal. 1851, 
p. 23, no. 99, as from Mazatlan, though he informs his readers that itis generally 
thought to be E, Indian, 
