THE NAUTILUS. dls 
As Dr. Cooper observed, this species is not as “ protean” as some 
others. It exhibits no such variations in form or color as B. proteus ; 
the latter assumes almost every mutation of form, but taken on the 
average is less acute and has the last whorl less patulously drawn 
out, axially, than the B. montezuma. The color of B. proteus is 
variably distributed, but tends in the most strongly colored exam- 
ples to be laid on in 4-6 broad, spiral bands of brown, with indis- 
tinet boundaries, separated by paler zones. In B. montezuma the 
color is seldom present, but, when it is, it is laid on in narrow, 
obscure zones, parallel with the incremental lines and never spirally 
disposed. The granulation in the Californian shell is less coarse 
and intense than in the Peruvian species when most developed, and 
the umbilicus averages much smaller in the former. All these char- 
acters are of degree rather than kind, but two features may be men- 
tioned which appear constant and specific. In the Mexican shell 
the angle which the outer lip makes with the body whorl, or axial 
perpendicular, at its junction is invariably more acute than in B. 
proteus, which latter has the lip bent suddenly down at this point. 
Secondly, the larval shell or nucleus of B. proteus is beautifully 
shagreened with minute punctations or short, almost vermicular, 
indentations, visible plainly under a glass, and only absent when 
worn off by abrasion. Traces of this sculpture may always be found. 
In B. montezuma the nucleus is delicately ribbed in harmony with 
the incremental lines, and does not show the peculiar shagreening 
alluded to, a character which alone is sufficient to establish its dis- 
tinctness, but the constancy of which could not be predicated from 
the three specimens examined by Mr. Binney. 
The distribution of the species now determined by Messrs Eisen 
and Belding is sufficient to disprove the hypothesis of introduction 
by artificial means, and it is satisfactory to have our largest North 
American species placed upon a permanent footing. 
EDIBLE MOLLUSKS OF SOUTHERN CALIFORNIA. 
BY MRS. M. BURTON WILLIAMSON, UNIVERSITY, LOS ANGELES CO., 
CAL. 
In an interesting article upon the “ Edible Mollusks of Rhode 
Island,” by Mr. Horace F. Carpenter, published in the Nauriius 
some time ago, he compares the number of ‘marine edible mollusks 
of Rhode Island with those reported from San Francisco by Profes- 
sor Keep. 
