REPORT ON THE CRINOIDEA. 243 
principally of headless stems of Bathycrinus aldrichianus, some with and some without 
the basal ring at the summit. 
Mr. Murray tells me that one specimen of “ Pterocrinus” was presented to the 
University Museum at Sydney by Sir Wyville Thomson, which indicates that there must 
have been several duplicates of the type. The only explanation of these facts which I 
can think of is, that Sir Wyville had not then (1874) made up his mind that the 
relatively large individuals dredged at Stations 106, 146, and 147 were generically 
identical with the small and immature specimen which he had described two years 
previously as the type of the new genus Bathycrinus ; so that he was led to give them the 
MS. name Pterocrinus, which he afterwards abandoned (1876) in favour of Bathycrinus. 
Bathycrinus gracilis, Wyville Thomson, 1872 (Pl. VIIa. figs. 1-3 ; woodcut, fig. 16). 
1872. Bathycrinus gracilis, Wyv. ‘Thoms., Proc. Roy. Soe. Edin., vol. vii, p. 772; The Depths 
of the Sea, pp. 450-454, fig. 75, 1873. 
Dimensions. 
Greatest length of stem (about forty joints), b F , 57°00 mm.! 
Longest stem-joints, ; : : ‘ : P : 2°50) ,, 
Length of head, . ; ; ; 3 : ; : 8:00 ,, 
Description of an Individual—sStem composed of about forty joints, of which the 
first ten or twelve are wider than high, increasing in thickness from above downwards. 
The following joints, at first cylindrical, increase rapidly in length, and acquire shghtly 
expanded ends, which become more and more marked in the lower joints, till the width 
of the end is 1 mm., twice the width of the shaft. The joints diminish in length towards 
the base of the stem, which ends in a small branching root. 
The basals are closely united into a smooth ring, the lower part of which is of the 
same size as the upper stem-joints, but expands gradually upwards.’ The radial pentagon 
above it expands more rapidly, so that there is a constriction at the basiradial suture, 
though not so marked as in Bathyeriius aldrichianus. The radials are strongly convex 
in the medio-dorsal line, but more flattened at the sides. Second radials nearly oblong, 
with a sharp median ridge and a slight hollow on either side of it. Axillaries shorter 
than the second radials and nearly oblong, and also marked by a sharp medio-dorsal 
ridge which forks about the middle of the joint, and is continued on to the three lowest 
brachials. There are only about twelve brachials in the arm, all of which are distinctly 
longer than wide, while the first two or three are scarcely wider than the rest, and have 
straight lateral edges like the radials. The later joints overlap rather sharply, so that 
the dorsal edge of the arm is serrate. The disk is unprotected by plates. 
Colour, in spirit, brownish-white. 
Locality — H.MLS. “ Porcupine,” 1869. Station 37. Lat. 47° 38’ N., long. 12° 8’ W.; 
1 Sir Wyville gave this measurement as 90 mm., which was possibly a misprint for 60. 
2 This expansion is not quite marked enough in the figure. 
