222 MARINE INVERTEBRATES 
FAMILY CIDARIDE 
Genus Cidaris 
C. tribuloides. Similar to Porocidaris sharreri, but with thicker and 
stouter spines. Found from South Carolina to Brazil. 
Genus Dorocidaris 
D. papillota. A deep-water species which occurs. off Chesapeake 
Bay and southward. It has slender spines with distinct longitudinal 
rows of serrations, and the spines are grouped in rosette-like forms over 
the small spherical body. 
D. Blakei. This speciesis very peculiar in having broad, fan-shaped 
spines; vermilion in color. Found in deep water in the Bahamas and 
West Indies. (Plate LVII.) 
Genus Porocidaris 
P. sharreri. This species occurs, in deep water, off the coast of North 
Carolina and thence southward to the West Indies. The shell is light 
greenish-pink. The spines are white, with brownish-pink at the base, 
pointed, three and a half inches long, and surrounded at the base with 
small, flat, triangular, secondary spines. (Plate LVI.) 
FAMILY ARBACIADE 
Genus Arbacia 
A. punctulata. A small species found in shallow water on shelly 
and gravelly bottoms from Massachusetts to Mexico, and common in 
Long Island Sound. The shell is about one inch in diameter; the spines 
are rather thick and one half to three quarters of an inch long. The 
color varies from deep violet — almost black —to straw-color, and the 
spines are tipped with brown. The South Carolina species are usually 
brick-red in the bare interambulacral spaces, with darker sutures, and 
spines tipped with same color. The animal walks by means of its spines, 
with a tilting motion, and advances quite rapidly. (Plate LVII.) 
Genus Celopleurus 
C. floridanus. This beautiful sea-urchin is taken on the Florida 
reefs. The very brittle spines are one to four inches long, and are 
banded with carmine and white. The shell has zones of light chocolate- 
color alternating with orange and yellow. 
FAMILY DIADEMATIDE 
GENUS Diadema 
_ D. setosum. Spines very brittle, and from one to two and a half 
inches long; jet-black. Found on the Florida reefs. (Plate LVII.) 
