A MONOGRAPH OF THE EXISTING CRINOIDS 151 



following have the distal edges all around produced and finely spinous. P 2 is 11 mm. 

 long, with 15 segments, exactly resembling P a . P„ is 8-10 mm. long, with 19 segments, 

 of which the basal are as small as the basal segments of P 2 . The first segment is 

 short, more or less crescentic, the second is about twice as broad as the median length, 

 the third is not quite so long as the distal breadth, the fourth is from one third to one 

 half again as long as broad, and the following gradually increase in length, after the 

 eighth being three or four times as long as broad; the fifth and following have slightly 

 produced and spinous distal edges. 



P 3 is 10 or 11 mm. long, similar to P b . P c is 8 mm. long, with 17 segments, 

 slenderer than P b and with more elongated segments. P 4 is similar to P . P d is 7 

 mm. long, with 18 segments, resembling P but even more delicate and with longer 

 segments. P 6 is similar to P d . P e is 6.5 mm. long, with 16 segments, and resembles 

 P d . P 6 is similar to P e . The distal pinnules are excessively slender, 8.5 mm. long, 

 composed of 20 segments. 



Each ambulacral lappet contains usually two similar smooth spicules, an outer 

 and an inner, the adjoining ends of which overlap more or less; each is bent at an 

 obtuse angle in the middle ; the outer may be branched or forked at the outer end, or 

 may be replaced by two or three small straight spicules irregularly arranged. 



Each tentacle contains at the base a double (distal and proximal) continuous 

 row of small spicules which soon coalesce, forming a single row which, becoming 

 gradually narrower, is continued almost to the tip; when the tentacle is contracted 

 this row of spicules may be more or less zigzag. These tentacular spicules are much 

 the most conspicuous of all the perisomic deposits in the pinnules. 



Locality.— Siboga station 167; near Misool Oat. 2°35'30"S., long. 131°26'12"E.); 

 95 meters; hard coarse sand; August 22, 1899 [A. H. Clark, 1912, 1918] (16, U.S.N.M., 

 E.426; Amsterdam Mus.). 



Remarks. — This very distinct species is as yet known only from the original 

 specimens dredged by the Siboga. 



EUDIOCRINUS PHILENOB A. H. Clark 



Plate 10, Figures 37, 38 



Eudiocrinus philenor A H Clark, Rec. Indian Mus., vol. 34, pt. 4, 1932, p. 551 (listed), p. 554 

 (Investigator station 534; description), pi. 19, figs. 1-4. 



Diagnostic features. — The cirri are long and slender but do not taper distally; 

 they are composed of 13-15 segments of which the longest are three and one-half to 

 four times as long as broad, and the distal are about twice as long as broad; the en- 

 larged proximal pinnules are not especially long; the arms are about 40 mm. long, and 

 the cirri are 10 mm. long. 



Description. — The centrodorsal is discoidal, thin, with a rather broad, flat, and 

 more or less rugose polar area. In small specimens the dorsal pole is more or less 

 strongly convex. The cirrus sockets are arranged in a crowded zigzag row, alternating 

 higher and lower; rarely there are two sockets one above the other. 



The cirri are XX-XXV, 13-15 (usually 14), 10 mm. long, slender and delicate 

 and only moderately curved. The first segment is very short, the second is longer, 

 about twice as broad as long or somewhat shorter, the third is half again as long as 

 the median width, the fourth is about three and one-half times as long as the median 



