WEST INDIAN STARFISHES 15 



sacks loosely surrounding the spines nearly or quite to the tips 

 when extended in life. They often have a formidable array of 

 minute sharp denticles, and are frequently very characteristic of 

 species. 



Subfamily Asteriin^. 



Asteriidce (restr.) Sladen, op. cit., 430, 560, 1889. Perrier, 1894, pp. 105, 



128; 1896, pp. 25-31. 

 Asteriince Verrill, op. cit., p. 42, 1914a. 



The AsternncB are chiefly characterized by the more or less 

 openly reticulated arrangement of the dorsal and lateral ossicles, 

 especially of the dorsal ossicles, which are usually more stellate 

 or lobulate and more slender than in the Stichaster group, and 

 generally united either by the ends of the lobes or apophyses, or 

 else by means of interpolated ossicles, thus allowing more flexi- 

 bility in the rays, and larger papular areas. The dorsal plates 

 may be in definite rows or irregularly reticulated. 



The Stichasterince, on the contrary, are chiefly characterized 

 by the more or less regular subtesselated or imbricated arrange- 

 ment of the ossicles, both on the sides and dorsal surface of the 

 rays, the ossicles themselves being larger, broader, and more 

 rhombic, and usually united in more definite, longitudinal and 

 transverse rows, vidth smaller and more regular intervening pap- 

 ular areas. In either group, as at present understood, the inter- 

 actinal plates may have the regular serial and subtesselated ar- 

 rangement. 



The discovery of many new generic and specific types inter- 

 mediate between typical Stichaster '' and Asterias, renders it 

 difficult to define the limits of the two so-called families, typified 

 by these genera. 



The only West Indian genus that has been referred to the 

 Stichasterinse is Stephanasterias. To me this seems to be more 

 nearly related to Leptasterias and therefore one of the Asteriinae. 



Genus Orth asterias Verrill. 

 Orthasterias Verrill, Starfishes North Pacific, pp. 168-185, 1914a. 



Long-rayed diplacanthid starfishes with a small disk. Dorsal 



7 The type of Stichaster is S. striatus M. and Tr. = S. aurantiacus of 

 later writers. It is a Chilian species. 



