MAZATLAN UNIVALVES 403 



This shell may be the C. achatinus of Menke, instead of the 

 next ? species. 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 Io7ig. 2' 18, lonff. spir. 'SS, lat.1'37, div. 110°. 



An elongated sp. „ 2-07, „ '3, „ 1-07, „ 110°. 



Sah. — 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 Bias, Sinds. — 

 Mazatlan ; extremely rare ; L'pool Col. 



Tablet 1923 contains 3 sp. somewhat varying.— 1924, 3 sp. 

 approaching C. regalitatis. 



477. CONTJS EEGALITATIS, SotO. 



Proc. Zool. Soc. 1834, p. 19. — 3£ilU. Sj/n. Nov. Test. Viv. 



p. IM.—S0W. Conch. III. pi. 57, f. Sl.—Rve. Conch. III. pi. 40, 



f. 218. — Lam. An. s. Vert. vol. xi. p. 133, no. 192. — Kien. 



Icon. Conch, p. 237, pi. 39, f. 3.— C. £. Ad. Pan. Shells, 



p. 109, no. 119. 

 P = C. achatinus, Jf/fce. in Zeit. f. Mai. 1847, p. 183, no. 23.* 



(non Briig.) 

 Chelyconus (Leptoconus) regalitatis, H. Sf A. Ad. Gen. i. 254. 

 ?An C. purpurascens, var. 



The few specimens belonging to this form were soon caught 

 ••ap 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 

 imiting 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, 

 laf. 1-1, div. 11". 



Sab. — 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. Mai. 1851, 

 p. 23, no. 99, as from Mazatlan, though he informs hia readers that it is generally 

 thought to be £. Indian, 



