MAZATLAN UNIVALVES 485 
not easily located elsewhere, it is here used in the enlarged 
sense. The present species approaches very nearly to R. costu- 
laris, Lam., R. gibbosus, Rve., and R. Californicus, A. Ad. It 
is known at once from Cuma costata by the roundness of the 
ribs, want of keel, and the greater narrowing and recurving of 
the canal. Although apparently of sedentary habits, not 
eating away obstructions in its shell close to the columella, it is 
remarkably free from the incrustations which usually cover C. 
costata. The form of the canal often irregularly apprOaches 
Cassis. The operculum closely resembles that of Cuma costata, 
differing in being somewhat more elongated, the pale margin 
not so distinctly marked off, and the surface rougher. The 
- largest sp. measures long.1°12, long. spir. 54, lat.° 67 div. 55°. 
A broad sp. Be aa84y ps °35)..h;5 Onn, eGo 
The most depressed sp. °57, oe 22.1 6), 7 DOn eae oo 
Hab.—Mazatlan ; rare; L’pool Col. 
Tablet 2278 contains 3sp. depressed form.—2279, 3 do. nor- 
mal shape.—2280, 3 de. acuminated. In the largest, a portion 
of the canaliferous rib remains, not eaten away, overhanging 
the labium.—2281, 4 sp. shewing the labrum at different stages 
of the coste.—2282, 4 sp. with 5, 6, 7 and 8 ribs respectively.— 
2283, 2sp. shewing extremes of sculpture.—2284, 2 sp. with 
opercula.—2285, 2 sp. with adhesions.— 2286, 2 sp. mended 
after fracture: one has formed a second canal; the other has 
twisted it back at an angle of 110°. 
Genus VITULARIA, Swains. 
Treatise, p . 297, 1840.— H.. & A. Ad. (inter Murices soperc. ign.) 
Gen. sail i. p. 74. Shell with very irregular varices ; oper- 
culum Purpuroid. 
612. ViTULARIA SALEBROSA, King. 
Murex salebrosus, King, Zool. Journ. vol. v. p. 347.—Sow. 
Conch. Ill. pl. 65, f. 48.— Kien. Icon. Conch. p. 121, pl. 47, 
f.1.—Lam. An. s. Veré. vol. ix. p. 613, no. 84.—Rve. Conch. 
Ic. pl. 24, f. 98.— Mike. in: Zeit. f. Mal. 1850, p. 187, no. 68.— 
C. B. Ad. Pan. Shells, p. 125, no. 142. 
_Fusus salebrosus, Horbes, Proc. Zool. Soc. 1850, p. 274, 
Murex vitulinus, Gray, Zool. Beech. Voy. pl. 33, f. 4,6; [non 
‘Lam. loc. cit. p. 595, no. 53:—= Murex purpura ( Chemn.) 
Desh, in noti:=M. miliaris, Gmel. Diliw. Wood. | 
