192 IOWA STUDIES IN NATURAL HISTORY 
color is uniform hair-brown the mouth is considerably in front 
of the center of the ventral surface and the anus is quite 
large and high up on the posterior truncated end. There are 
four genital pores and the ambulacral rosette is slightly sunk- 
en, but the anterior petal is almost obliterated and disappears 
on the ventral side of the animal. The peripetalous fasciole is 
quite evident and forms re-entrant angles between the petals. 
The anal fasciole and plastron are plainly seen and the latter — 
is relatively large. The tubercles on the ventral plastron are 
not notably larger than those foundrelsewhere. The delicate 
spines which are borne on the fascioles are compactly arranged 
and erect like a close fence. There are three kinds of pedicel- 
lariw, all three-pronged. The largest kind has very slender, 
much-curved prongs, each of which describes nearly a perfect 
semicircle from base to tip, the three together enclosing a 
spherical space: The other two are much like those of ordi- 
nary sea-urchins, being pyriform in shape and differing mainly 
in the fact that one kind is borne on a relatively long stalk, 
while the other is nearly sessile. 
On opening a specimen, the intestine was found to be coiled 
like a watchspring, making a little more than two complete 
revolutions. In life the ambulacral feet are extended at times 
considerably in advance of the spines, and are provided with 
suckers. 
Ophiuroidea—The serpent stars were numerous although, on 
account of being unable to dredge successfully in relatively deep 
water, it is probable that not so many novelties were secured 
here as at Barbados. At both places Ophiocoma echinata was 
by far the most abundant form and wriggled out from almost 
every overturned stone. The variations in color were exceed- 
ingly great and would form an interesting study. One of the 
most common disk markings was a pentagonal cream colored 
area on the disk, sharply outlined against a dark umber brown 
background. Some specimens have a spread of more than a foot. 
From the wide distribution of this species in the West Indies 
and its excessive abundance in shallow water, it has evidently 
attained a marked success in the struggle for existence. It 
would be exceedingly interesting to know just what character 
