382 Gould's Descriptions of Shells 
On a critical comparison of the California with W. India specimens, 
the following differences seem to be constant, so far as these speci- 
mens are concerned. 
W. INDIA. CALIFORNIA. 
Form strictly pyramidal. ore elevated pyramid. 
Whorls very s v convex, suture Put decidedly convex and more 
somewhat constrict | girt in at the suture. 
Surface, corrugate or yr at right | Surface without undulations but girdled 
angles with the lines of increment. by a few obsolete ridges on the last 
mmules confused or blotched. whorl. 
Base with no tendency to distinct tes- | Fulgurations well defined. 
sellation. ase more or less tessellated with 
Lip black at edge, submargin dead| ranges of squarish black spots. 
white. Lip nacreous and iridescent to the 
Aperture very oblique, its lip regularly | margin. 
sloping from junction to periphery. | Aperture less oblique, lip arched. 
Columellar tooth well marked. Columellar tooth obsolete; inner lip 
Columellar lip somewhat sinuous. forming a regular sweep 
As I have seen no young specimens from California, it is not 
unlikely that some of the above diagnostic marks may not prove 
constant in some st —the more elevated form, more convex 
whorls, and Macias p undulations may be regarded as the most 
important characters. I present this comparison for verification 
when more numerous specimens shall have been obtained. Should 
the differences prove constant, it will be one of the most remarkable 
examples of analogous species from correlative regions. 
TROCHUS (MONODONTA) PYRIFORMIS. 
T. ovato-conica, crassa, striis obtusis remotis antic? cincta, nigra, flavido 
oblique et undulatim lineolata; spira conica, anfr. sex convexiusculis, ad peri- 
pheriam rotundatis; basis convexa, fovea umbilicali albo-cinctá notata, imper- 
forata; apertura cirea columella acuta, bidenticulata ; labro acuto nigro ; 
m alba. 
Shell thick and heavy, elevated ovate pyramidal, eroded at tips 
without sculpture, bluish-black, or with a few obtuse revolving lines 
on the last whorl, with numerous oblique, fine, undulating stripes 
of yellowish crossing the lines of growth nearly at right angles: 
Whorls six, slightly convex ; suture linear ; periphery of the last 
whorl obtusely rounded ; E convex, white at centre, with a small 
