The smallest individual of the above lot, one-fourth of an inch long, 
had four holes; the largest, about 2 inches in length, had six holes; but 
there did not appear to be any regular increase in the number of holes in 
proportion to the size or age of the shells. 
Further examination and close study of these young shells reveals the 
fact that when the young creature emerges from the egg, the nucleus, 
or first whorl of its shell, is white in color and without sculpturing or 
holes. About the time one whorl is added to this embryonic shell the 
holes and sculpturing appear, and at the same time the little shell, in 
some instances at least, assumes a dirty brick-red color, but soon changes 
into the normal shading of brown or blue, while a few shells before me 
are of a beautiful shade of dark green. 
The holes or perforations are arranged in a serial row on the left dorsal 
side of the shell, and are a little tubular until the shell attains about 2 
inches in length. They are generally circular in form, but oblong holes 
frequently appear with the circular ones in the same individual. The 
sculpturing consists of a few oblique or curved radiating ridges passing 
from the nucleus to the holes, over which there passes from eight to twelve 
wavy spiral threads, a little corded sometimes by the sharp striz of growth. 
The interstices formed by the intersecting ridges and spiral threads 
often show as deep pits, and especially so in certain shades of light, which 
gives that part of the little shell near the nucleus a reticulated appear- 
ance and adds much to its beauty. With the increase of age and size 
these sculpture characters change greatly, and even disappear altogether 
on many of the adult shells. Frequently, however, the spiral threads of 
the young can be traced on the back of the adults, as low, obscure ribs, 
wavy or corrugated, and in a few instances the whole back of the shell is 
covered with obscure corrugations, giving stich shells quite a distinct 
aspect. 
Flaliot’s cracherodii (Leach), var. californiensts (Swainson), 
The shells of this interesting variety found on Guadalupe Island) 
Lower California, are peculiar. 
The perforations are smaller, more numerous, generally circular, re- 
seinbling gimlet holes in a piece of wood, closer set together, while the 
entire row is often higher up on the back of the shell than in the normal 
or typical shells of //. cracherodit. 
This combination of characters conspire to give these shells quite a 
distinct aspect of their own, and notwithstanding that there are numerous 
intermediates. between the extreme forms of these shells and the typical 
H. cracherodii, 1 think it well for the purposes of study and the illus- 
tration of variation to retain Swainson’s name, Californiensis, for those 
shells with the small holes without regard to their number on a single 
