242 THE VOYAGE OF H.M.S. CHALLENGER. 
about the centre of the joint, and is continued on to each of the arm-bases, where it disappears 
after about the first eight joints. These have sharp lateral edges where their flattened 
sides meet the dorsal surface. The first three or four are wider than long, their successors 
gradually becoming more cylindrical, but never much longer than wide and not over- 
lapping, so that the dorsal surface is smooth. The third joint is sometimes the only free 
one, all its successors being united in pairs; while in another case the fourth is free as 
well as the third, and also the seventh and tenth, the intermediate pairs being united. 
In a third variety three pairs after the third brachial are united, and the tenth is free 
again, while the remainder of the arm is normal. There are fifty jomts in an arm 
30 mm. long (fide C. W. T.). 
The first pinnule is generally on the ninth, but sometimes not till the eleventh 
brachial. The pinnule attachment is near the end of the joint, so that the socket enters 
into the composition of the terminal face (Pl. VIla. fig. 21). The joints of the lower 
pinnules are not greatly larger than those of their successors. The disk is unprotected 
by plates. 
Colour, in spirit, white. 
About a dozen heads and several stems, some retaining the basals. 
Localities —Station 146. December 29, 1873; lat. 46° 46’ 8, long. 45° 31’ E.; 
1375 fathoms ; Globigerina ooze ; bottom temperature 36°°6 F. 
Station 147. December 30, 1873; lat. 46° 16’ S., long. 48° 27’ E.; 1600 fathoms ; 
Diatom ooze ; bottom temperature 34°°2 F. 
| have no record respecting the number of individuals obtained at each Station. 
According to Sir Wyville Thomson" this species “ seems to be widely distributed ; we 
have detected fragments of it at at least six or seven Stations in the Atlantic and the 
Southern Sea.” 
Remarks.—The head of this species is readily distinguished from that of Bathycrinus 
campbellianus by the calyx being constricted at the basiradial suture, and not in the 
radial funnel above it; by the greater width of the arm-bases, and by the smoother 
dorsal surface of the arms. In the first of these characters it resembles Bathycrinus 
carpenteri, so far as can be made out from Danielssen and Koren’s figure; but it is much 
more robust than the northern species, in which the axillaries are considerably shorter 
than the second radials, while the lower stem-joints are relatively longer, and have much 
more expanded ends than those of Bathycrinus aldrichianus, in which the dice-box shape 
is less apparent. 
When the collection of Stalked Crinoids came into my hands, I found one bottle 
labelled “ Pterocrinus and Hyocrinus, Stations 146 and 147.” As I had never heard of 
the former genus, my curiosity was much excited, and it was with considerable 
disappointment that I found the contents of the bottle, besides Hyocrinus, to consist 
1 Journ, Linn. Soc. Lond. (Zool.), vol, xiii. p. 51 (1876) 1878. 
