REPORT ON THE ASTEROIDEA. 235 



from the infero-marginal plates. All these actinal intermediate plates bear uniform 

 squamule-like papillae invested with membranous sacs. 



Adambulacral plates large and pentagonal in shape. Armature consisting of: — (1.) 

 An angulated furrow series of five short, subequal, papilliform spinelets, the median one 

 being triangular in section. (2.) On the actinal surface two longitudinal series of short, 

 flattened spinelets, the inner series often disposed in such a manner as to close against the 

 furrow series, thus forming perhaps an incipient pedicellarian apparatus. All the spinelets 

 are in membranous sheaths. 



Madreporiform body small, oval, and situated about its own diameter distant from the 

 margin of the paxillar area. 



No pedicellarise are present. 



Remarks. — This genus is distinguished from Bathybiaster by the presence of the 

 epiproctal cone, and by the absence of the pedicellarise which specially characterise the 

 latter form. 



The genus Eyaster, established by Danielssen and Koren ' for the reception of a small 

 Asterid furnished with a remarkably developed epiproctal prolongation, dredged during 

 the Norwegian North Atlantic Expedition, is probably more nearly related to this genus 

 than to any other form with which we are acquainted. So far as I am able to judge from 

 the description and figures alone, the position of Eyaster in the tabular scheme of the 

 family would probably be adjacent to Phoxaster, and perhaps intermediate between that 

 genus and Bathybiaster. It differs from Phoxaster by the extraordinary development of 

 the " dorsal appendage " and by the character of the armature of the adambulacral plates ; 

 furthermore, as no mention is made in the careful description given by its authors of any 

 special membranous investment of the general tegumentary spinulation or granulation, 

 Eyaster probably differs in that respect also. 



Respecting the dorsal appendage, it may be remarked that the difference in the relative 

 size of that structure in Eyaster and Phoxaster is not greater than that existing between 

 different species belonging to the genus Porcellanaster ; for instance, between Porcel- 

 lanaster cceruleus and Porcellanaster caulifer. The structure of the prolongation, 

 however, would appear to be much more specialised in llyaster than in Phoxaster. I 

 fully share with the learned describers of Eyaster their doubt as to its being an adult 

 form. 



I have on a preceding page (pp. 131, 132) stated my opinion that this elongate 

 epiproctal prolongation is in no way homologous to the stem of a Crinoid, as maintained 

 by Drs Danielssen and Koren. 2 



1 Ntjt Mag. f. Naturvidenslc, Bd. xxviii. lste Hefte, p. 4, tab. i. ii. figs. 15-19; Den Norske Nordhavs- 

 Expedition, 1876-78, Zoologi, xi. Asteroidea, 1884, p. 100, tab. vii. figs. 15-19. 

 * Loc. cit., pp. 102, 103. 



