424 MR. W. p. SLADEN ON THE ASTEROIDEA 



Od the Asteroidea and Echinoidea of the Korean Seas. 

 By W. PERcr Sladen, F.L.S., F.G.S. 



[Eead June 6, 1878.] 



(Plate VIII.) 



The Echinoderms collected by Capt. St. John whilst surveying 

 in the Straits of the Korea and neighbouring Japanese waters, 

 were intrusted by Dr. J. Grwyn Jeffreys and Dr. Giinther to Prof. 

 P. Martin Duncan, to whose kindness in placing the material in 

 my hands I owe the pleasure of presenting the following commu- 

 nication upon the small but very interesting series of Asteroidea 

 and Echinoidea. It is only justice due to Capt. St. John to remark 

 that the value of the present collection is enhanced by his very 

 careful registration of the exact position and depth at wbich the 

 specimens were taken ; whilst the importance of the Echinoderms 

 themselves is increased by the fact that many of them belong to 

 forms hitherto little known or imperfectly described ; in addi- 

 tion to which several are represented by small and premature 

 growth-stages, which enable us to fill in phases in the life-history 

 of the species to which they belong. The association of several 

 of the species will also be found full of particular interest. 



Holding the opinion that the duty of a naturalist is not com- 

 pleted by the simple determination of mere lists of species from 

 a given locality, but rather that it lies in pointing out what 

 variations are undergone by known " forms " from the general 

 type in order to attest the results of the conditions of the special 

 habitat, it has been the aim of the author to indicate as far as he 

 was able the particular modifications presented in the cases under 

 notice, or at least to denote the grounds on which the determina- 

 tions rest. 



ASTEEOIDEA. 



ASTEOPECTEN FORMOSUS, Sp. UOV. PL VIII. figS. 1, 2, 3, 4. 



Coll. St. John : Korea, 36 and 54 fathoms (young); W. Coast 

 of Nipon, 60 fathoms. 



Disk large, rays short, arm-angles widely rounded ; the greater 

 and lesser radii of the largest specimen measure respectively 14-5 

 millims. and 5*2 millims., or in the proportion of 2f : 1 approxi- 

 mately. The foot-papillae, which are all cylindrical and taper 

 towards the tip, form two series : the inner one, which spreads 



