54 



SIDONOPS BICOLOR. 



umbilicus usually have an elongated (Plate 11, fig. 12), those remote from the 

 umbilicus, a circular or polygonal (Plate 11, figs. 13, 14) transverse section. 

 Each ray bears a terminal verticil of from two to eight stout, conical, lateral 

 spines arising vertically from the ray. 



The young sterrasters observed in great numbers in the choanosome of 

 the specimens from Stations 3168 and 4420 were surrounded by stratified 

 capsules readily stainable with azure and apparently composed of flat endothelial 

 cells. The smallest of these young sterrasters was a sphere, 20 ^ in diameter, 

 composed of exceedingly fine radial rays. 



DIMENSIONS OF STERRASTERS. 





2958 



2981 



3168 



4420 



4531 



4.551 



Length /i 



130-145 



145-170 



140-165 



135-155 



135-155 



140-145 



Breadth /< 



100-120 



105-133 



105-120 



105-118 



115-120 



100-120 



Thickness /t 



80-92 



90-97 



85-90 



85-87 



88-90 



77-85 



LOCALITY AND NATURE OF ENVIRONMENT. 



No. of 

 Station 



Locality 



Date 



Depth 



Bottom 

 tempera- 

 ture 



Bottom 



No. of 

 specimens 



2958 



Off southern California, 34° 04' 

 N., 120° 19' 30" W. 



9 Feb., 1889 



47 m. 

 (26 f.) 



12.7° 

 (54. 9° F.) 



Gray sand 



1 



2981 



Off southern California, 33° IS' 

 N., 119° 24' W. 



13 Feb., 1889 



82 m. 

 (45 f.) 





Coarse gray sand 

 and broken shells 



2 



3168 



Off central California, 38° 01' 

 25" N., 123° 26' 55" W. 



24 March, 

 1890 



64 m. 

 (34 f.) 





Rocks and corals 



4 



4420 



Off southern California, E. of 

 Point San Nicolas Island, S. 

 77° W. 10.5 km. (5.7 miles), 

 drift S. 60° W. 



12 April, 

 1904 



58-60 m. 

 (32-33 f.) 





Fine gray sand 



4 



4.531 



Monterey Bay, Cal., Point 

 Pinos Light House. N.64°E., 

 3.8 km. (2.1 miles). 



28 May, 

 1904 







Fine gray sand, 

 pebbles, and rock 



3 



4551 



Monterey Bay, Cal., Point 

 Pinos Light House, S. 9° E., 

 8.4 km. (4.5 miles), drift S. 37° 

 E. 



7 June, 

 1904 



102 m. 



(56 f.) 





Coarse .sand, 

 shells, and rock 



1 



