332 MAZATLAN UNIVALVES 
The above series, arranged from their predominating colours, 
mutually pass into each other. They present the extremes of 
form and sculpture, and several possess their opercula. Tablet 
1569 contains 3 sp. richly coloured and sculptured, with pro- 
jecting ridges of growth conspicuous near the mouth—1570, 
2 sp. after severe fractures, spire twisted. 
Tablet 1571 contains a minute specimen, ‘038 by ‘02, which 
may belong to this species, but develops the spiral keel much 
earlier and more strongly than usual. 
380. TURRITELLA TIGRINA, Aven. 
Icon. Conch. p. 29, no. 22, pl. 4, f. 2.—Rve. Conch. Ic. pl. 3, 
sp. 8.—Mke. in Zeit. f. Mal. 1850, p. 164, no. 10. 
Haustator (Turritella) tigrina, H. g A. Ad. Gen. i. 352. 
=T. imbricata, ke. (quasi Lam.) Zeit. f. Mal. 1847, p. 178, 
no. 3. 
Comp. T. Cumingil, Ave. loc. cit. pl. 4, sp. 13. (Panama, 
11—16 fm. Cuming ; Conchagua, Belcher ; Gulf of California, 
sandy mud at low water, Rev.—Steel.) 
Comp. T. imbricata, (Zam. var.) Kien. loc. cit. p. 11, no. 8, 
pl. 9, f. 2a. 
(Light var.) Comp. T. leucostoma, Val. Rec. Obs. vol. ii. 
p. 275 :— Kien. loc. cit. pl. 6, f.2:—Rve. loc. cit. pl. 2, f. 5. 
(Acapulco, Humboldt & Bonpland; Gulf Nicoyo, sandy 
mud, 11 fm., Cuming.) 
Very few specimens, and those for the most part dead, were 
found of this species. It is not swollen in the middle of the 
spire; the periphery has a blunt angle; and the upper whirls 
have at least five spiral lirule. The usual painting is a pre- 
vailing white, with large purple-black patches : but sometimes 
the coloured part is light reddish brown, very ill defined. 
Operculum with about 17 whirls, the outer ones fringed with 
a lighter colour, transversely wrinkled, and with a few spiral 
rows of hairy tubercles. A specimen with 22 whirls measures 
long. 3°33, long. spir. 2°87, lat. °76, div. 15°. 
Hab.— Gulf of California, Reeve—Mazatlan ; extremely rare ; 
L’pool Col. 
Tablet 1572 contains a young sp. of 5 whirls, measuring ‘049 
by ‘O18. The first two are smooth; the rest much rounded, 
with fine spiral strie. 
Tablet 1573 contains 2 normal sp., one with operculum, the 
other after acid.—1574, 1 sp. light var. 
