PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 765 



pole is small and practically flat. In lateral view the centrodorsal appears thin discoidal 

 with a single row of cirrus sockets, four to each radial area. 



The cirri are unknown. 



The radials are barely visible beyond the rim of the centrodorsal; their distal 

 angles are slightly separated. The IBr : are very short, about six times as broad as 

 long, the sides of adjacent IB^ being parallel to each other and slightly separated. 

 The IBr 2 (axillaries) are twice as broad as long, almost triangular, with the distal 

 angle produced, the anterior sides concave, and the lateral angles slightly produced and 

 ending in a fringe of fine spines. 



The 10 arms measure 14 mm. from the radials to the eighteenth brachial. 



Syzygies occur between brachials 3+4, 9 + 10, and 14 + 15, and distally at inter- 

 vals of 3 muscular articulations. 



PI is 5.5 mm. long, with 13 segments, exceedingly slender and hairlike. The first 

 segment is twice as broad as long, the second is slightly longer than broad, the third is 

 slightly over twice as long as broad, and the following increase in length so that the 

 distal are excessively elongated with swollen articulations. The pinnule tapers gradu- 

 ally to the fifth segment and is extremely slender from that point onward. P 2 is 3.5 

 mm. long, with 8 segments, of which the first is broader than long, the second is slightly 

 longer than broad, and the remainder are excessively elongated and slender; it is just 

 perceptibly smaller basally than PI. P 3 is 3 mm. long, with 8 segments, and resembles 

 P 3 . The following pinnules are all broken; but the segments of all of them, except for 

 the first two, are excessively elongated. 



Locality. Laccadive Sea (lat. 717'30" N., long. 7654'30" E.); 786 meters; tem- 

 perature 3.3 C.; gray mud; August 19, 1897 [A. H. Clark, 1912] (1, I.M.). 



THAUMATOMETRA. sp. A 



[See vol. 1, pt. 2, pi. 57, fig. 1362] 



Antedon spec, (abyssicola Carp.?) HARTLAUB, Bull. Mus. Comp. Zool., vol. 27, No. 4, 1895, p. 146 



(Albatross sta. 3381; characters), p. 148, pi. 4, fig. 25. 

 Balhymetra, sp. DALL, Bull. Mus. Comp. Zool., vol. 43, No. 6, 1908, pp. 317, 318 (diagnosis of Stilifer 



[Mucronalia] bathymetrae) . A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 245 (from 



Hartlaub); Die Crinolden der Antarktis, 1915, p. 147 (from Hartlaub). BARTSCH, Proc. U.S. 



Nat. Mus., vol. 53, 1917, pp. 300, 353 (from Dall), pi. 49, fig. 3 (after Hartlaub). 



Characters. The single specimen from this station lacks the cirri, the arms beyond 

 the first syzygy, and the pinnules beyond a few of the basal segments. 



As described by Hartlaub the centrodorsal is conical and bears about 25 cirrus 

 sockets which are relatively large and closely crowded. The radials arc entirely 

 exposed, their interradial angles being a little produced between the bases of the IBrj 

 so that these are not in lateral contact. 



Hartlaub compared it with Bathymetra abyssicola, but from his figure it seems to be 

 a partially decalcified example of some species of Thaumatometra. 



Locality. Albatross station 3381 ; in the vicinity of Malpelo Island, Bay of Panama 

 (lat. 456'00" N., long. 8052'30" W.); 3239 meters; temperature 2.11 C.; green 

 mud; March 6, 1S91 [Hartlaub, 1895]. 



Eemarks, This specimen had attached to it a parasitic gastropod of the genus 

 Stilijer belonging, according to Prof, von Martens, to the subgenus Mucronalia. 



