622 



ECHINODERMATA 



genera with more than a hundred species ; in almost all seas from shallow 

 water to 2,900 fathoms, among rocks or hydroid or coral colonies or in 

 algae, climbing about actively by means of their arms and cirri or 

 swimming about slowly. 



ANTEDON Freminville. Mouth central and ambulacral grooves 

 equal in length; pinnules smooth, one or more of the proximal elon- 

 gated and flagellate ; centrodorsal hemispherical or nearly discoidal, with 

 10 to 30 cirri: 35 species. 



Fig. 967 



Fig. 968 



Fig. 967 tlsocrinus asterfos (Leunis). Fig. 968 Antedon tenella a young, attached 

 individual (Verrill). 1, basal; 2, radial; 3, brachial. 



A. tenella (Retzius) (A. dentata Say) (Fig. 968). Ten arms; cen- 

 trodorsal with 25 to 30 cirri, each with 10 to 16 segments ; diameter 6 cm. : 

 Atlantic coast, in 35 to 600 fathoms, from New Jersey northwards. 



FAMILY 5. COMASTERIDAE. 



Similar to the Antedonidae, but differing in that the mouth is excen- 

 tric, the ambulacral grooves are of unequal length, the proximal pinnules 

 are serrated, and the centrodorsal is discoidal with few or no cirri: a 

 dozen genera and numerous species; in all warm seas, chiefly in shallow 

 water. 



1. NEOCOMATELLA A. H. Clark (Comatula Lamarck; Actinometra 

 J. Muller). Outer segments of cirri with slight dorsal processes; arms 

 more than 10: 1 species. 



