40 VERRILL 



Subfamily HELIASTERIN^. 



Subfamily Heliasterina Viguier. Family Heliasterida Perrier; Sladen. 



The Heliasterinse do not seem to me to be worthy of more than 

 subfamily rank. They agree with Asteriid2e in nearly all important 

 structural characters. They differ mainly in having very numerous 

 short rays and a very broad disk, but in these respects they are 

 closely approached by Pycnopodia and Ccelasterias. Their dorsal, 

 ventral, and ambulacral skeletons are distinctly like Asteriidae. The 

 only distinctive characters of much value are the restriction of the 

 stomach to the disk by a discobrachial septum, and the existence of 

 double septa between the rays. 



The group, which includes only the genus Heliasfer, is confined to 

 the Pacific coast of America and the adjacent islands, from Chile to 

 Lower California. (See H. L. Clark, op. cit, 1907, plates i-viii, for 

 details of structure and descriptions of all the species.) 



Subfamily PYCNOPODIIN^. 

 For the characters of this subfamily, see below, p. 197. 



Subfamily STICHASTERINM. 



The most developed forms of Stichasterinae,' e. g., Stichaster 

 striatus = aurantiacus, have several regular rows of interactinal 

 plates ; other forms have only one or two rows. Some of the As- 

 teriinae (Calasterias, Pisaster, etc.) also have from three to six rows 

 of such plates. On the other hand, some forms of Stichasterinse 

 (Stichasirella rosea, Stephanasterias albula, and Granaster) have 

 the dorsal ossicles more or less irregularly arranged ; and even the 

 median row may not be distinct in 5. albula. In the latter the ven- 

 tral plates bear longer spinules. Ca-lasterias V. is an intermediate 

 genus with multiple rays. 



The Stichasterinae have, at present, no known representatives on 

 the northwestern coast, unless we so reckon the Stephanasterias 



^Stichaster M. and Tr. (April, 1840) was monotypic. Its type was 5. stria- 

 tus M. and Tr. = Asterias aurantiaca Meyen {not of Linne) = Tonia atlantica 

 Gray (Sept., 1840). Tonia is a complete synonym of Stichaster, which has 

 about six months priority. The European species, A. rosea, usually referred 

 to Stichaster, and taken as its type by many writers, is a distinct genus which, 

 so far as I know, has no valid name. It may be called STICHASTRELLA, 

 5". rosea being the type. It has two or three rows of interactinal plates; 

 adambulacral plates bear two or three spines irregularly. Carinal rows of 

 plates and spinules are usually distinct, but only by the slightly larger size 

 of the plates. 



