MAZATLAN UNIVALVES 243 
tion, and closer wrinkles entering the umbilicus. On one (dead) 
specimen however the radiating ruge are coarse, not inter- 
rupted by spiral lines; the periphery also is more adherent to 
the penultimate whirl. Four (perfect) specimens only were 
found of this exquisitely beautiful species. Long. ‘02, lat. *052 
by °043. Div. about 170°. 
Hab.— Mazatlan: off Spondylus ecaleifer, extremely rare ; 
L’pool Col. 
Tablet 1154 contains one specimen. 
304. VITRINELLA PERPARVA, C. B. Ad. var. NODOSA. 
V.t. discoided, planata, quadratd, subhyaliné ; carinis diubus 
spiralibus infra et supra peripheriam planatam, quarum postica 
nodosa ad marginem spiralem est; basi rugulis radiantibus 
distantibus ornatd; carind parum expressd regionem wnbili- 
calem magnam circumeunte; apertura quadraté; anfr. ult. 
haud declivi. 
Pan. Shells, no. 265, pp. 187, 316. 
V. nodosa, P. P. C. Cat. Prov. 
The characteristic coronation of the upper keel is not men- 
. tioned by Prof. Adams ; it is however very conspicuous in the 
specimen sent to Mr. Cuming. It is possible that the specimen 
he described is another species, in which case the name which 
I had given may be retained for this. It closely resembles in 
outline a smooth, crenated Dundry Ammonite. In Mr. Cum- 
ing’s specimen, there are one and a half normal whirls; there 
also appears a slight labial deposit. The only specimen found 
at Mazatlan is immature, and measures long. ‘0075, lat. °033 
by °027, div. 175°. 
Hab.—Panama; 3°sp. in sand; CO. B. Adams. — Mazatlan ; 
1 sp. off Spondylus ; L’pool Col. 
Tablet 1155 contains the specimen. 
305. VITRINELLA ExIGuA, C. B. Ad. 
V. t. subdiscoided, alba, anfractibus iv. et triente ; carinis ili. 
maxime prominentibus, acutis, angulatis, haud serratis, quarwm 
wna ad peripheriam, una antica, una postica in spird site sunt ; 
angulo circa umbilicum magnum plus minusve monstrante ; striis 
exitllimis spiralihus totd superficie ornatd ; lirulis radiantibus 
plus minusve distantibus et infra et supra decussantibus, cirea 
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