MONOGKAPH OF THE EXISTING CRINOIDS. 551 



No. 42 (fig. 937, p. 549) : Dredged on November 9, 1902, at a depth of 385 meters. 



Total length, 25 mm. 



There are 53 columnals and a terminal stem plate. 



The 10 proximal columnals are very short and discoidal; the longest are 

 about six times as long as broad, with slightly enlarged ends. 



The terminal stem plate is rounded, with two blunt digitiform processes. 



There is as yet no trace of the formation of the centrodorsal. The middle 

 of the proximal border of each basal, which overhangs the proximal columnals, 

 shows a prominent notch. 



Between the radials, which have become relatively narrow and are now no 

 wider than the IBr t which they bear, are large and prominent interradials which 

 are about two-thirds as long and about two-thirds as broad as the radials on either 

 side of them and rest upon the broadly truncated distal angles of the basals. 



The radianal, reduced in size, is entirely excluded from the radial circlet and 

 lies just beyond the posterior interradial, in contact with rather more than the 

 right half of its distal border, and in contact with the left-hand border of the 

 IBr, borne by the right posterior radial. 



The IBr 2 are more or less squarish in shape, and of the same width as the 

 radials which bear them. The IBr, are shield shaped, distally as broad as the IBr,. 



There were probably four or five brachials beyond the IBr 2 . 



No. 43 : Dredged on June 14, 1902, in 180 fathoms. 



Total length (distal portion of column missing), 65 mm.; length of crown, 

 12.5 mm. 



As preserved the column, with the centrodorsal, consists of 65 segments. 



The centrodorsal is rounded conical, as in fully grown specimens, with the 

 tip truncated, and about as high as broad. It bears three irregular rows of large 

 cirrus sockets, of which the lowest are radial in position, the middle interradial, 

 and the proximal, nearest the periphery of the centrodorsal, again radial. 



The columnal immediately beneath the centrodorsal is discoidal, seven or eight 

 times as broad as long, with the sides as seen in profile sloping inward and down- 

 ward. Its diameter is slightly greater than that of the centrodorsal at its base 

 and apparently at least twice as great as that of the truncated tip. 



On its proximal side it bears about the periphery five conspicuous triangular 

 plates which are just in contact laterally, and proximally extend upward between 

 the bases of the lowest cirri, reaching a height equal to nearly or quite twice the 

 length of the underlying columnal. The texture of these plates and of the under- 

 lying columnal is very coarse, much coarser than that of any of the elements of 

 the crown. The inner surface, which is very uneven, slopes inward and down- 

 ward, but how far they extend inward it is impossible to determine. As these 

 plates arise from the outer edge of the columnal bearing them and lean slightly 

 outward, they extend very considerably beyond the converging sides of the distal 

 portion of the centrodorsal, so that the latter is seen to rest upon the central 

 portion of a rosette formed of five wedges triangular in section, tapering inwardly, 

 and placed side by side. 



142140 21 Bull. 82 R7 



