CAKE-URCHINS 225 
the cone in straight lines, and around the base is a depressed area which 
emphasizes a thick border which extends around the scalloped margin. 
The ¢olor is light yellowish-brown. (Plate LVIII.) 
GENus Echinanthus 
E. rosaceus. This is a large species, cblong in shape, about four to 
five inches across and much rounded on top, the body being about two 
inches thick. The ambulacral zones 
are depressed, leaving prominent 
elevations which make a very con- 
spicuous figure on the top. The color 
is light chocolate-brown. -Found 
close to the shore off the coasts of 
Florida, South Carolina, and the 
West Indies. 
FAMILY SCUTELLIDE 
Genus Echinarachnius 
THE SAND-DOLLARS 
E. parma. Thisspecies, the shells 
of which are very common objects pininarachni ineanna Ashes OnGe: 
on sand-beaches from New Jersey “70” Snatter than natural sive 
northward, is generally known as the 
sand-dollar. The animals have flat circular disks about three inches in 
diameter. The ambulacral zones, in five petal-like lines, form a distinct 
figure on the upper surface. The mouth is in the center of the ventral 
surface, and the excretory opening is on the edge of the disk. In life 
they are covered with short, fine, silky spines, which seem like hair, and 
are purplish-brown in color, but turn green when taken from the water. 
The sand-dollars are exceedingly abundant off Nantucket Shoals, where 
the bottom seems paved with them. They are eaten in great numbers 
by flounders, cod, and haddock. When put in alcohol they stain it a 
dark color. Fishermen prepare an indelible ink by grinding to powder 
these animals and mixing it with some liquid. This species is also found 
on the northern Pacific coast. 
E. excentricus. This is the common sand-dollar of the Pacific 
coast. The disk, instead of being circular as in EZ. parma, is somewhat 
straight across the posterior end, and the posterior ambulacral zones are 
shorter than the other three. The upper side of the disk is raised, form- 
ing a cone-like elevation, the apex being the center of the figure. 
Genus Mellita 
M. testudinata. The disk is rounded in front and straight in the 
back. Four long, narrow lunales, or cuts, occur on the sides in line 
with the ambulacral, petal-shaped zones, but do not extend quite to the 
edge of the disk; and a wide’ lunale occurs in the interambulacral space 
15 
