Vol. XXIX, pp. 1-6 January 25, 1916 



PROCEEDINGS 



OF THE 



BIOLOGICAL SOCIETY OF WASHINGTON 



rt-' 



NOTES ON THE SYSTEMATIC POSITION OF CERTAIN 

 GENERA AND HIGHER GROUPS OF STARFISHES. 



BY WALTER K. FISHER. 



The Goniopectinid^. — In "Asteroidea of the North Pacific 

 and adjacent Waters"* the family Goniopectinidae, proposed 

 by Professor A. E. Verrill, was said to differ from the family 

 Porcellanasteridse in having double ampullse connected with the 

 tube-feet (p. 19), and in having an intestine and intestinal 

 coecum. The component genera of the Goniopectinidee, Gonio- 

 pecten and Prionaster, bear the closest resemblance to Ctenodiscus, 

 although the rays of the latter are short while in the Goniopec- 

 tinidse they are long and slender. This resemblance results 

 from the similar characteristic biserial arrangement of the skin- 

 covered actinal plates with the intervening fasciolar channels, 

 the similar structure of the marginals, between which are 

 cribriform organs, and the similar form and armature of the 

 adambulacral and mouth plates. Recently Mr. A. H. Clark 

 found, in a specimen of Prionaster elegans Verrill, single am- 

 pullae, thus breaking down one of the principal differences 

 between Ctenodiscus and the Goniopectinidee. I have again 

 examined the ampulla? in a very large Prionaster megaloplaz 

 Fisher, and in Goniopecten asiaticus Fisher, and have also verified 

 the structure of these organs, as described, in Goniopecten dem- 

 onstrans Perrier. All of these have single ampullae, what I 

 formerly regarded as the lower lobe of the ampulla, or as a 

 second ampulla, being a swelling probably due to the extreme 

 contraction of the muscular vescicles. If the swelling has any 

 significance at all, it is the merest rudiment of a ventral lobe, 



• Bulletin 76, U. S. National Museum, 1911, part 1. 



1— Proc. Biol. Soc. Wash., Vol. XXIX, 1916. (1) 



