7 
1877.] COLLECTION MADE BY H.M.S. ‘ PETEREL,.’ 71 
12, Hipponyx GRAYANA, var., Menke. 
A young shell, apparently belonging to this species, differs from 
the normal form in being much more coarsely radiately costated ; 
and consequently the crenulation of the basal margin is considerably 
more conspicuous. 
13. Rissoma stricta, Menke. 
The single specimen from the Galapagos Islands agrees very closely 
with the description given by Menke (Zeitschrift fiir Malokozoologie, 
1850, p. 177). The labrum is very greatly thickened, and the 
transverse liration is strongly developed around the lower half of the 
body-whorl. The whorls are ten in number, and have about twenty 
smooth ribs, which are slightly flexuous on the last. Fig. 25, on 
plate iii. of Schwartz von Mohrenstein’s monograph of the genus, 
gives a very good representation of this species. 
14. Trocuus (Ompaatius) cooKsont, sp.n. (Plate XI. fig. 7.) 
Testa valde umbilicata, suborbiculata, levissime conoidea, fusco 
roseoque variegata, lineis albidis nigro articulatis obscure picta ; 
anfractus 43, sublevigati, converiusculi, striis spiralibus paucis 
tenuibus insculpti ; ultimus Superne convexus, infra suturam 
leviter depressus, ad peripheriam complanatus, idcirco biangu- 
latus, basi subplanus, tenuissime spiraliter striatus, circa um- 
bilicum sulco haud profundo aratus; umbilicus albus, profundus, 
callo albido, ad basim columelle dentem Sormante circumdatus ; 
apertura suborbicularis ; columella arcuata, anfractui callo 
juneta. 
Diam. maxima 8 millim., minima 7, alt. 4. 
This shell is deeply umbilicated, elevately orbicular, convex above, 
only slightly conical and flat beneath ; the last whorl is flattened at 
its middle ; and this produces a double angulation, which, however, 
is not very conspicuous; there is also a faint depression a little below 
the suture. The coloration of this species is not very definite ; the 
upper surface is blotched irregularly with pink and brown, and some 
spiral, articulated lines, the base is a trifle paler ; the only sculpture 
consists of fine spiral striations, which are most conspicuous on the 
base; the callus which surrounds the umbilicus is whitish, and ter- 
minates in a faint tooth on the columella, and is bordered by a 
shallow sulcus in the whorl. The columella terminates above in a 
callosity which extends upward some distance on the whorl, and 
also spreads out within the aperture. 
T. occultus of Philippi, bears a faint relationship to this form, but 
is more conoid and more strongly sculptured. 
15, FissureLua opscura, Sowerby. 
16. Curron (Lopuyrus) GoopALLII, Broderip. 
17. Curron (Lornyrvs) sutcarus, Wood. 
