236 MAZATLAN UNIVALVES 
with Bryozoa and Annelids attached.—1143, 1 sp. with a 
ment of Calyptreid. 
Tablet 1144 contains 4 opercula. 
294. OMPHALIUS GLOBULUS, 7. s. 
O. t. parva, globulosd, compacta, subconicd ; anfractibus v. et 
dimidium, quorum ii: et dim. primi subleves, alteri spiraliter 
tenue lirati ; livis sublevibus, interstitiis latis ; peripheria haud 
angulata ; wmbilico haud magno, spiraliter ascendente ; callosi- 
tate parietali haud conspicud, ab axi subdistante ; regione win- 
bilicali subconcavo, liris spiralibus fortioribus ; columella tuber- 
culo magno et callositate basali plus minusve distinctad munita, 
prope eas profunde insculpté; labro intus haud calloso; sub 
epidermide tenui, leviori, pallide purpureo-cinered, punctis et 
maculis purpureis picta. 
Comp. Trochus glomus, Whe. in Zeit. f. Mal. 1850, p. 173, 
no. 35: non Phil. in Kust. Mart. pl. 14, f. 15 (non 17 ;= 
Clanculus g. H. §& A. Ad. Gen. 1. 416,) 
This shell is much more clevated and compact than the 
young of even the most conical variety of O. ligulatus; in 
sculpture and umbilicus more resembling O. viridulug, Its 
characteristic features however are the absence of the ttitbercle 
which in O. ligulatus always borders on the spiral columellar 
callosity, and the deep channeling of the adjacent area. The 
size of the umbilicus varies slightly. Long. °3, lat. °33, div. 80°. 
Hab.— Mazatlan ; 5 sp. only ; L’pool Col. 
Tablet 1145 contains the most characteristic specimen. 
Genus VITRINELLA, C. B. Ad. 
Testa Margarita, Cyclostremati seu Adeorbi-formé simulans ; 
minima, albida, subdiaphana, tenuis, plerumque subhyalina ; 
superficie interdum levi, plerumque sculpturd varie ornaté ; 
anfractibus paucis, quorum plures sculpture desunt, normales 
L-i., rapide augentibus ; umbilico maximo. 
Mon. Vitr. 1850 :—Pan. Shells, p. 184: (pars..—Phil. Handb. | 
Conch. p.207.—H. &§ A. Ad. Gen. vol.i. p. 434.—(Non Gray, 
B. M. Cat. Pulm. p. 65, 1855.) 
This genus, constituted by Prof. Adams for 5 species from 
Jamaica, (of which one, V. megastoma, is an Ethalia,) and 
