— —=——_ » , = 
~ a Poe 
GASTEROPODA. 57 
all the volutions. The aperture is somewhat rhomboidal, conforming 
to the angles of the whorl; lip consisting of one of the rib-like promi- 
nences ; a single linear lamella revolves on the axial side of the aper- 
ture. 
Diameter one-fifth of an inch ; axis one-twelfth of an inch. 
From the island of Maui, Sandwich Islands. 
This is, perhaps, the most beautiful species of the group. It is 
distinguished by its angular whorls, and by its lamellar ridges, more 
prominent than in any other species, projecting at the periphery so 
as to cause it to resemble the rowel of a spur. Only three or four 
specimens were obtained. 
Figures 52+, 52+ a, 52+ d, three views of the shell enlarged ; 52¢c, 
natural size. 
Hetix Cressipa (Gould). 
Testa variabilis, solida, depressa, lenticularis, acute carinata, nitida, 
dense et acuté striata, fasciis flavo-viridibus et castaners coalescentt- 
bus cincta, infra sub-planulata, umbilico magno et profundo perfo- 
rata: spira anfractibus quinque viz convexts: apertura triangularis ; 
labro acuto ; fauce hlacind. 
Heliz Cressida, Goutp; Proceed. Boston Soc. Nat. Hist., 11. 176. 
Sept. 1846. Expedition Shells, 23. Prerrrer ; Monog. Helic., 1. 123. 
SueE.1 depressed, lenticular, very acute at periphery, about equally 
convex above and below, rather solid, shining, but obliquely striated 
with crowded, very delicate, and sharp lines of growth. General 
colour yellowish-green, varying to rusty, and generally banded above 
with darker chestnut, the colours blending at contact; sometimes 
there is also a band underneath. Whorls five, or somewhat more, 
scarcely convex or depressed at suture, so as to form a low dome. 
Umbilicus commencing rather suddenly, very broad, and penetrating 
to the summit. Aperture transverse, triangular ; throat pale lilac. 
15 
