1918 Bush: on Echinoderms 31 



ven' narrow. Color yellowish, with a red spot or circle on the disk and 

 markings on the rays. — Numerous, in deep water. 



Family PTERASTERIDAE 

 Genus Pteraster 

 Rays 5 to 8, usually 5. Ambulacral groove turned up distally to 

 upper side; transverse fans of adambulacral spines varying in size, 5 or 6 

 to each fan. Ambulacral feet in 2 rows, orange in color. 



1. Pteraster tesselatus Ives. Cushion Star 



Pteraster reticulatus Verrill. 

 As described for the genus. — Rather numerous, in deep water. 



ORDER PHANEROZONA 



KEY TO FAMILIES 



A. Surface rough ; disk flat. 



B, Disk large; rays short. goniasteridae (p. 31) 



BB. Disk small; rays long. Luidiidae (p. 32) 



AA. Surface smooth; disk plump. asteropidae (p. 33) 



Family GONIASTERIDAE 



key to genera 



A. Rays very short. ceram aster (p. 31) 



AA. Rays longer, as long as the disk is broad. mediaster (p. 32) 



Genus Ceramaster 

 Form short-rayed, stellate. Dorsal plates numerous, closely united, 

 roundish or hexagonal, granulated; marginal plates regular, corresponding 

 closely, closely granulated, or the naked central areas with rows of granules 

 around the margin, and the plates forming the margin of the disk and 

 rays ; interactinal plates like a mosaic, granulated ; papular areas small ; 

 adambulacral spines numerous, small, crowded, grading into actinal gran- 

 ulations. 



1. Ceramaster granulans (Retzius) Verrill. 



Asterias (jranularis Retzius; Astrogonium granulare MUller & Trochel; 

 Goniaster granularis Liitken ; Pentagonaster granularis Perrier; Tosia 

 (Ceramaster) granularis Verrill. 



Rays 5, very short ; disk pentagonal, flat. Dorsal plates hexagonal, 

 closely united, leaving papular pores corresponding to the angles ; plates 

 covered with small granules ; marginal plates prominent, covered with 

 similar small granules ; actinal plates crowded, polygonal, covered with 

 spinules of various sizes ; adambulacral spines forming a simple marginal 

 row ; actinal groups of spinules varying in size ; oral spines many, short, 



