76 ON THE ECHINODEKMATA OF THE 



The three radial plates are visible; the first is a very short band-like plate at the 

 margin of the centrodorsal ; the second is comparatively long, and diminishes with a 

 somewhat rapid but graceful curve into a neck-like form at the distal extremity upon 

 which the axillary radial is articulated ; and there occurs in the median dorsal line a 

 slight prominence or lip opposed to the proximal angle of the axillary. This latter, 

 which is the third radial plate, is quadrately diamond-shaped in its outer contour, 

 and somewhat broader than long, the distal angle being more obtuse and the margins 

 of the distal facets much less incurved than in the preceding species. The first 

 brachials are also relatively longer and more conspicuous than in A. Eschrichtii ; and 

 the second brachials are subtriangular or even subcrescentiform in profile (as seen from 

 outside), and are broader than long, their apex being brought forward very considerably 

 to the front. The third brachial, which bears the first syzygy, is nearly as long as 

 broad. At some distance from the disk the joints of the ray are almost as long at their 

 deepest part (i. e. on their longer side) as they are broad, the length of the shorter side 

 being, perhaps, rather more than one third of the breadth on the lower third of the 

 ray. The sutures of the joints are not nearly so much inclined as in A. Eschrichtii', and 

 the joints diminish in length as they approach the extremity of the ray. Syzygies 

 occur normally on the 3rd, 8th, 12th, 15th brachial, and so on although the second is 

 sometimes found on the 9th, the third on the loth or 14th, and the fourth on the 16th 

 or 17th brachial joint. 



80-90 pinnules occur along one side of a ray. The arms, as a whole, are long, 

 tapering, and decidedly delicate in character, although so numerously pinnulated ; 

 whilst the narrowness of the calyx, the angle of ray-attachment, and the comparative 

 shortness of the pinnules give a very long and narrow appearance to the closed plume. 



The first and second pinnules are equal in length, measuring 15 millims., and 

 contain 36 joints each. The third pinnule is very much smaller, being scarcely 

 11 millims. long, and with only 23 joints. One from the middle of the ray has like- 

 wise 23 joints, and measures 15 to 16 millims. long. In another specimen the first 

 pinnule had 37 joints, and the third 18. The joints on the proximal third of the first 

 three pinnules have the dorsal side produced into flattened processes, similar to those 

 developed much more prominently in the last species. The pinnules beyond the first 

 three have very much longer joints, as will be seen by reference to the measures 

 above given ; and these are also more cylindrical in shape. In these pinnules, further- 

 more, the first two joints are much flatter, broader, and shorter than the rest, but do not 

 present the conspicuous character noted in A. Eschrichtii. The ovarial sacs are thin, 

 delicate, and semitransparent, presenting a very marked difference in comparison with 

 those of the latter species. 



Remarks. It is not without considerable hesitation that we have referred the form 

 under notice to Barrett's species ; for the original diagnosis is so meagre that little can 

 be made out of it. Dr. Marenzeller, however, has given a perfectly intelligible and 

 more comprehensive sketch of (what is in our opinion) the same species, in the 

 description which accompanies his determination of examples obtained by the Austro- 

 Hungarian Arctic Expedition, with which specimens ours would seem to accord in all 

 essential particulars. 



