MAZATLAN UNIVALVES ~ 497 
theless the points of difference above indicated being constant, 
it did not seem allowable to unite them completely. Long. °63, 
long. spir. °28, lat. °4, div. 50°. 
Hab.—Mazatlan ; extremely rare ; L’pool Col. 
Tablet 2393 contains a sp. kindly presented by J. W. White- 
head, Esq. of Liverpool. 
! 
625. Nassa (?PAGODUS, var.) ACUTA. 
N. t. pagodiformi, albidd, rubrofusco tinctd, intus violascente ; 
anfr. nucleosis i. levibus; dein anfr. vi. normalibus, valde 
tumentibus, suturd parum excavatda, a costis undulata; costis 
vadiantibus circiter ix. haud latis, haud acutis, colore intensiore, 
interstitiis latis ; costis ultimis antice subobsoletis ; lirulis 
spiralibus crebris, extantibus, costis superantibus, supra costis 
subtuberculosis ; apertura subquadrata, antice lata; labro et 
labio acuto, extantibus, haud reflexis ; labro antice sinuato, ad 
dorsum varicoso, intus tenue lirato, lird ultima guxta canalem 
extante ; labio lird parietali conspicud, plicd guxta canalem 
valde extante, alterd subobsoleté > canali valde intorto, con- 
spicuo ; operculo serrato. 
Comp. Triton pagodus, Rve. Conch. Ic. pl. 20, sp. 97 :=Nassa 
p. C. B. Ad. Pan. Shells, p. 63, no. 50. 
Comp. Buccinum decussatum, tien. Icon. Conch. p. 109, 
no. 106, pl. 30, f.3:=(Nassa) Hima decussata, H. & A. Ad. 
Gen. 1. 121. 
The very beautiful Mazatlan shells were at first identified 
with an E. Indian species in the Cumingian collection, which 
may be the true N. polygonata of Lam. This however differed 
from the species as figured by Aven.; and, there being no 
W. Coast shell among Mr. Cuming’s Nasse at all resembling 
it, the N. acuta was described as new. But the Triton pagodus 
has evidently so much in common, that a collation of types 
(at present impossible) may prove them identical. If so, the 
error must be attributed to the unfortunate location of this 
very decided Nassid among the Tritons. LKiener’s species, 
assigned by him to Africa, is identified with the Pacific shell 
by Prof. Adams: it may however be an analogous species, as in 
the case of N. tiarula and N. tegula. A dwarf adult, possessing 
the ordinary number of whirls, and a normally-sized mucleus, 
measures ‘53 by °36; the largest sp. measures long. °83, 
long. spir. 44, lat. °6, div. 60°. 
