156 PROCEEDINGS OF THE CALIFORNIA 
instead of being held in place by a system of muscles. On the lower or 
actinal surface ambulacral furrows, crowded with small pores, and arranged 
irregularly, take the place of ambulacra. The ambulacra of the upper or 
abactinal surface are broader than the interambulacra. 
Family CLYPEASTRIDH. 
Echini with supports connecting the upper and lower floors of the test, 
either as pillars, walls, or radiating partitions. 
ECHINOCYAMUS. 
24. HE. pusillus, Gray. Norway. Mediterranean. Azores. Florida. 
CLYPEASTER. 
25. C.rotundas. Panama. Gulf of California. San Diego. 
The fine specimen from the Gulf of California, in this collection, is of a 
dark violet tint, which is its color when alive. 
26. OC. scutiformis. Red Sea. Philippine Islands. Kingsmills. Japan. 
It has been my good fortune to examine a large number of specimens from 
Japan and the Pacific islands, obtained by various persons, among them 
W. Garratt and W. J. Fisher. These specimens, which are 13% to above 4 
inches in length, all evidently belong to one species, and that species a 
Clypeaster, and not an Echinanthus, since there are no double floors or double 
walls. As the small specimens agree exactly with the C. scutiformis of 
Samk., it is evident that the larger ones are the adults of that species. 
The three specimens in the collection measure respectively 13, 2;5;, and 
314 inches in longitudinal diameter, and 1;4;, 14, and 3} inches in transverse 
diameter; but I have seen specimens exceeding the largest of these. 
Family LAGANIDA. 
Floors of test connected by walls running parallel to the edge; interambu- 
lacra extremely narrow. 
LAGANUM. 
27. L. depressum, Sess. Kingsmills. VitiIsland. Philippines. Australia. 
Zanzibar. 
Two small specimens, one of which measures 1} inch longitudinal diame- 
ter by 1} inch transverse diameter, appear to be the young of this species. 
They are from the Kingsmills. The partitions, forming a narrow belt of 
three or four concentric walls near the edge of the test, agree with Laganum 
proper, not with Peronella. 
Family SCUTELLID. 
Test extremely flat, frequently perforated with cuts or lunules. Ambula- 
eral furrows of under side more or less branching; tubercles and spines of 
upper and lower surfaces differing in size. 
