480 MAZATLAN UNIVALVES 
Purpura speciosa, Rve. Conch. Jc. pl. 11, f.56.—Vail. Rec. 
Obs. vol. i. p. 316, (1833.) 
(Purpura) Thalessa speciosa, H. & A. Ad. Gen. i. 127. 
= Purpura centiquadra, Val. ins. 
The species was described by Blainville from a single young 
specimen brought from ‘“‘California” by M. Botta. Although 
not figured, its recorded analogy with the W. Indian P. del- 
toidea, orange mouth, and numerous close violet bands of 
colour, leave no doubt of the identity of the shell. It is said 
to be finely striated at the base, but this character may be 
accidental. The three rows of nodules are generally seen in 
the young shell, but often only one appears on the adult. The 
violet bands are broken up into rectangular dots. The labrum 
is not toothed, but sometimes finely serrate at the margin. 
Operculum purple black, with lighter wings: outside very 
glossy. Scar very finely corrugated transversely, with the 
few lines of growth somewhat rectangular. Most of the speci- 
mens are about an inch long: a giant measures dong. 1°82, 
long. spir. °58, lat. 1°46, div. 90°. 
Hab.—Acapuleo, Humboldt § Bonpland.—Mazatlan ; 1 young 
sp.; Botta.—Do.; rare, generally incrusied with coralline ; 
T’pool Col. 
Tablet 2248 contains 3 sp. triserial.—2249, 3 do. with two 
rows becoming obsolete.—-2250, the largest specimen.—2251, 
2 separate opercula ; two others are in situ in the shells. 
608. PuRPURA TRIANGULARIS, Blainv. 
Monogr. Purp. in Nouv. Ann. Mus. vol. i. 1832, p. 223, no. 46 
(bis), pl. 11, f. 4, (t. jun.)— Desh. in Lam. An. s. Vert. vol. x. 
p. 115, no. 82. 
Purpura Carolensis, Rve. Conch. Ic. pl. 11, sp. 57, 1846.— 
C. B. Ad. Pan. Shells, p. 76, no. 69. 
(Purpura} Tribulus Carolensis, H. & A. Ad. Gen. i. 126. 
The solitary young specimen brought by M. Botta from 
Mazatlan, and figured by Blainville, was overlooked by Mr. 
Reeve, who named it from Charles Is., Galapagos, whence it 
was brought by Mr. Cuming. It is easily distinguished from 
P. triserialis by its more rounded outline, white mouth, double 
row of tubercles, infrasutural spiral rib forming a slight pos- 
terior canal, finely plaited labrum, 4-dentate internally, labium 
finely corrugated near the base, and surface crowded with 
