84 IOWA STUDIES IN NATURAL HISTORY 
cases, chocolate and orange yellow. The delicate spines are very 
active at times, when first taken from the water. Another very 
beautiful species is Salenia pattersonuw, with vermillion and white 
spines. Several specimens allied to Cidaris were secured, among 
them probably C. tribuloides. and Dorocidaris papillata. 
Only one species of spantangoid was taken, Echinoneus semv- 
lunaris, brown in color and with the ambulacral grooves ex- 
tending all the way around to the mouth. There are four geni- 
tal pores, and both mouth and anus are ventral. This species 
lives buried several inches in the sand beneath rocks. Fisher 
was the first of our party to discover its habitat. 
Dr. Fisher has kindly supplied the following notes regarding 
the Holothurians: One of the commonest littoral forms at Peli- 
ean Island was Holothuria arenicola which occurred under 
water-worn beach rocks at high-tide level. The animals were 
buried in the sand, head downward, in such a way that the 
rocks formed a protection above them. Normally, the anal 
aperture was at the surface of the sand just where the latter 
met the stone. These sea cucumbers were found in a narrow 
zone at mean high-tide level, so that an ordinary slight degree 
of low tide would uncover them. In the same narrow strip grew 
a sparse filamentous green alga attached to the beach-worn 
rocks. Under each stone the holothurians were sometimes fairly 
crowded. This species like many of the fossorial forms, has a 
narrow circle of small tentacles, is rather tolerant of abuse in 
‘‘killing mixtures,’’ but care must be taken to kill them expanded. 
Synaptula vivipara—Dr. Fisher states that in digging in a 
patch of eel-grass for this species he found only one specimen, 
whose head was subsequently lost, so that the record is not 
certain. A good deal of digging was subsequently done, both at 
Pelican Island and at Antigua, for this form; but no other 
specimen were found. 
The Ophiuroidea of the expedition will be reported on by 
Dr. Austin H. Clark of the National Museum. The fol- 
lowing notes were taken in the field. By far the most 
abundant species was Ophiocoma echinata, which occurred al- 
most literally under every stone and scuttled away with amaz- 
ing celerity when disturbed. 
It is most commonly brown in color, with the club-shaped 
