CLARK: THE STARFISHES OF THE GENUS HELIASTER. 71 



A. Agassiz, '77. 



North American Starfishes. Mem. M. C. Z., 5, No. 1. 



No mention is made of either Heliaster or Labidiaster, nor can I find 

 the slightest hint of the writer's opinion on the position of either genus. 

 I may add further that Mr. Agassiz assures me that he has never 

 expressed or held any such opinion as is here ascribed to him. 



Perrier, '93. 



Traite de Zoologie. Premiere partie. Paris, 1893. 



The author makes no direct reference to the question, but the position 

 he assigns to Heliaster might not unfairly be interpreted as showing that 

 he holds the view ascribed to him. 



Ludwig, '97. 



Die Seesterne des Mittelmeeres. 



I have been able to find no reference whatever to any one of the three 

 genera concerned, though I have very carefully and repeatedly examined 

 this splendid monograph. 



Studer, '84. 



Abh. d. k. Akad. d. Wiss. zu Berlin, p. 1-64. 



No reference whatever is made to either Heliaster or Pycnopodia. 



Viguier, '78. 



Arch, de Zool. exp. et gen., 7, p. 33-250. 



Although the author does not make any positive statement as to the 

 relationship of Pycnopodia and Heliaster, it is clear from his remarks on 

 page 116 that he does not consider them closely allied, while the state- 

 ments on pages 118-119 indicate that he does consider Heliaster as 

 intermediate between the Asteriidae and Brisingidae (to which family 

 Labidiaster is commonly assigned), while Labidiaster, he thinks, may be 

 intermediate between Heliaster and Brisinga. 



It is clear, therefore, that the only "general agreement" which these 

 five authors show is in avoiding the expression of any such opinion as 

 is ascribed to them. It is very difficult to understand why Ritter and 

 Crocker should have given these references at all, for they certainly do 

 not support their contention, even indirectly. 



On comparing specimens of the three genera concerned it will be seen 

 that superficially they are somewhat similar, but that the more numer- 

 ous rays and the larger disc ally Labidiaster and Heliaster more closely 

 to each other than to Pycnopodia, although the stout abactinal skele- 

 ton of Heliaster separates it from both. The ambulacra in Pycnopodia 

 are moreover very broad, and the pedicels are distinctly quadriserial 

 almost to the actinostome, while in Heliaster the ambulacra are nar- 



