230 PROF. BELL ON BATHYBIASTER VEXILLIFER. [A.pr. 7, 



groove. Along the top, the middle and the base of each side, there 

 runs a row of short, sharpish spines ; the uppermost of them is 

 wanting near the disc and the lowermost fades out near the tip of the 

 arm. 



The arrangement of the paxillse can be seen from the drawings 

 given herewith; as there is but a single specimen I have not removed 

 the upper plates or injured the type in any way (Plate XXIV. fig. 3). 



There can be little doubt that this species has a small anus, and it 

 will be remembered that Sir Wyville Thomson regarded it as au 

 Archaster and not as an Astropecten. The definition of the genus as 

 given by Messrs. Koren and Danielssen must be so far modified as 

 to run "Anus present or absent " (cf. Plate XXIV. fig. 6). 



The colour of the dried specimen is light yellow ; Thomson states 

 that during life it is of a pale rose, with a tinge of buff, the suckers 

 semi-transparent and pale pink. 



The single specimen recorded by Thomson was dredged at 

 " Station 76 " by H.M.S. Porcupine in 1869 ; Faeroe Channel, eo"" 

 36' N., 3° 9' W., 344 fms. 



The specific characters may be thus stated : — ■ 



E=5r. 



Arms and disc flat, the former with deep vertical sides formed by 

 the marginals, of which there are about 70 in each row ; those of the 

 superomarginal series have each a single short spine near the upper 

 edge, and the inferomarginal similar and subequal spines near the 

 upper and lower edges. The adambulacral spines are arranged by 

 fours on two sides of a triangular plate, the apex of which looks into 

 the furrow and bears a spine. Connected with this spine is a grooved 

 spiniform body or " vexillum," whicii may be an aborted pedicellaria, 

 and the edges of which are finely denticulated. A small anal orifice. 

 Madreporite small, near margin of disc. 



Generic Affinities. — The general characters of this form obviously 

 ally it to Batliybiaster, as Messrs. Koren and Danielssen suggested, 

 hut it appears to be necessary to make some m.odifications of the 

 original generic diagnosis. 



The first statement is that the body is flat ; to this B. loripes var. 

 obesa is an exception. 



The next is " 5-rayed, with an extremely wide ambulacral furrow, 

 having long pedunculated, peculiar pedicellarise along its margins." 

 I am inclined to suggest that the expression " peculiar pedicellarise " 

 might be replaced by the indifferent term " vexillum." Owing to the 

 dried condition of Thomson's specimen, I cannot make any addition 

 to or critical remark on the descriptions of previous writers, but it will 

 be remembered that the learned Norwegian natuialists recognize the 

 great differences between these appendages and normal pedicellariae, 

 and that Thomson says no more than that they may be " abortive 

 pedicellarise." In Mr. Sladen's species the structures at the sides of 

 the ambulacral grooves are not pedunculate pedicellariae placed on an 

 adambulacral spine, and I very much doubt whether that form should 



