40 S. goto; 



that Bcnlhopeden spinosus is distinct, but tliat Sladen's Pararclicister armatvs 

 is the same as ArcJiaster simplex described by Peeeier in 1881, and should 

 consequently be known as Benthopeden simplex. According to Sladen, however, 

 Peeeier's figure ' is altogether unlike the smallest example of P. arnrntus in 

 cliaracter of armature lx)th of adambulacral and infero-marginal plates.' Under 

 these circumstîiuces it seems best, provisionally, to retain Sladen's name. 



" It may be noted, however, that the elongated disc spines which are 

 so noticeable in B. spinosus are not to be foimd in any of the Iiisli speci- 

 mens of B. armatus. In the largest Iiish specimen (Il=ca. 60 mm.) the 

 largest disc spine measures only 1.5 mm., while in a specimen of B. spinosus 

 in the British Museum (R = 95 mm.) the disc spines are as much as 7 mm. 

 long, and in a smaller specimen (R = 50nmi.) they measure 2.5 mm. The 

 large interbrachial spines in the latter specimen measra'e only 6 mm., whereas 

 in Irisli specimens of 11 = 40 mm. they reach a length of 8 mm. It was 

 only in the largest Irish specimen (11 = ca. 60 mm.) that the comb-shaped 

 pedicellarise could be found." 



Cheir aster oxyacanthtis (Sladen). 



Tliis species is not represented in any of the collections studied by 

 me. The folloAving is the original description of Sladen ['89. p. 38] : 



" Pontaster oxyaccmthus, n. sp. (PI. IX. figs. 1 and 2 ; PI. XII. figs. 7 

 and 8). 



"Kays five. 11 = 73 mm. ; r = llmm. Il>6.5 r. Breadth of a ray near 

 the base, 11 mm. 



" Bays elongate, tapering continuously from the base to the extremity, 

 the outer part naiTow and attenuate, and of great flexibility, the outer part 

 in the specimen imder notice curled round with an abactinal recm-vature. 

 Interbrachial arcs well-rounded. Abactinal smface x>laiie- Actiual surface 

 subplane. Lateral walls of the rays comparatively high and vertica.1. 



" The general paxillsB of the abactinal sm'face are comparatively small 

 and simple, closely placed on the disk and inner part of the rays, but 

 diminish gi-eatly in size as they proceed outward, and are more widely 



