GASTEROPODS 359 - 
animal is removed, it displays a most beautiful and highly colored 
nacreous surface. The spot near the center of the inner shell 
surface where the muscles of the foot were attached is usually 
most brilliantly colored. The shell of the abalone is susceptible 
of taking a very high degree of polish, and is extensively used in 
commerce for colored mother-of-pearl and for inlaid work. Hal- 
iotis is a vegetable-feeding genus. They cling with great tenacity 
to rocks about low tide, and it requires skill to remove them with- 
out breaking the shell. There are several species in California. 
The Chinese use the abalone for food, and have waged a persis- 
tent war upon the family along the Pacific coast until the speci- 
mens are not nearly as commonasformerly. They are also eaten 
in France and in Japan. 
H. splendens. The largest and perhaps the most attractive in 
appearance of the Californian species. Speaking of this beautiful shell, 
Professor Keep says: ‘‘ Within, a whole rainbow is condensed in one of 
the magnificent shells, though the shades of green are most conspicuous. 
The coloring in the center is particularly fine, resembling a peacock’s 
tail. There are about six open holes near one side of the shell, and its 
length is about the same number of inches.” (Plate LXVI.) 
» rufescens. A large abalone, which sometimes attains a length of 
eight or nine inches. It is red in color, with three open holes in the 
body-whorl. The outer portion of the shell is usually incrusted with 
mineral deposit and overgrown with vegetation. 
H. cracherodii. Very dark green without, with five to nine holes; 
length from one to six inches; spire exceedingly short. Common on the 
Californian coast in crevices of rocks at low tide. 
FAMILY TROCHIDE 
This is one of the largest and most interesting families of the 
Mollusca. It contains many apparently widely separated genera 
and a host of species, which for the most part are littoral, the 
majority actually living between tide-marks. The typical trochid 
shell is top-shaped or pyramidal, having a broad base and many 
closely wound flat whorls terminating in a sharp apex. All the 
trochids are nacreous within the aperture—a character which is 
constant throughout the family. The animal has but one gill ° 
(the left), a short snout, and often frontal lobes on the head. 
The edge of the mantle or the epipodial line of the foot is usually 
ornamented with from three to five cirri. The tentacles are 
