212 MARINE INVERTEBRATES 
FaMILy HELIASTERIDE 
Genus Heliaster 
H. multiradiata. Spines on the upper surface of rays in five rows, 
but close to the disk proper become reduced to one row. Found on 
the coasts of Lower California and Mexico. (Plate LIV.) 
FAMILY ASTERIDE 
The Asteriide have the following characteristics : four rows 
of tube-feet; ossicles small and unequal; spines isolated or 
grouped; pedicellarie of two forms, forceps-like and scissors-like 
respectively. They include the very common forms found on all 
beaches. 
Genus Asterias 
A. vulgaris. The common starfish of the Atlantic coast, from Long 
Island Sound to Labrador. It occurs at low-water mark and extends into 
deep water. It has five arms, which taper to a point. Large specimens 
measure fifteen inches across. The upper surface is rough, being cov- 
ered with short spines, which are largest and thickest at the edges of the 
rays, and surrounding them are the pedicellariz. The color varies from 
pink, yellow, and brown to purple. : 
A. Forbesii. The common starfish of the Atlantic coast, from Massa- 
chusetts Bay to the Gulf of Mexico. This species resembles very closely 
A. vulgaris, but can, be distinguished from it by the madreporic plate, 
which is bright orange, while in the former it has the same color as the 
animal ; also the arms are a little swollen at the base and terminate more 
bluntly. These two species are very destructive to oyster-beds, espe- 
cially where their ranges overlap. It is computed that they destroy 
annually two hundred thousand dollars’ worth of oysters. Vast numbers 
congregate where the feeding-ground is good, and move in long lines from 
place to place. The oystermen dredge over the beds and bring them 
up in thousands, then steam them or throw them on the shore above 
high-water mark. (Plate LIV.) 
A. ochracea. The common starfish of the Pacific coast, from Sitka to 
San Diego. Five rays, each hardly twice as long as the diameter of 
the body; spines running irregularly over the surface, but forming a 
pentagon at the middle of the disk and inclosing the madreporie plate ; 
diameter eight inches. It is very common near San Francisco on rocks 
at low-water mark. (Plate LIV.) 
_ A. gigantea. Body very large and swollen; six rays, somewhat less 
in length than twice the diameter of the disk; aboral surface covered 
with numerous short, blunt, equidistant spines of uniform size and 
regularly distributed ; spines contracted at the base and striated; diam- 
eter two feet. Found on the California coast. 
