PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 731 



Abnormal specimen. The single individual from Challenger station 218 is peculiar 

 in having an additional ossicle in one of the IBr series inserted between the two normal 

 elements. This ossicle is about half as high as the IBri, and appears to be con- 

 nected with the IBr] by a straight muscular articulation and with the IBrj by synarthry. 



Notes [by A.M.C.]. The Challenger specimen has the centrodorsal low, rounded 

 conical; 1.5 mm. in basal diameter and 1.0 mm. in height. The cirrus sockets are ar- 

 ranged in 15 almost perfectly regular vertical columns of usually 3 sockets in each so that 

 the total number is XL-XLV. No cirri remain. The figure in the Challenger Report, 

 pi. 32, fig. 6, does not bring out the columnar arrangement of the cirrus sockets. 



As in the Siboga specimen the rugous patches on the sides of the division series 

 and proximal brachials are very conspicuous and the water pores are again notably "-)-"- 

 shaped. The width at the first syzygy is 1.0 mm. and the length from IBr! to Br 

 is 7.0 mm. 



The longest remaining PI has 11 segments and measures 4 mm. When complete it 

 probably had about 15 segments and was at least 1 mm. longer. 



P 2 has 10 segments and is 3.5 mm. long. The segments are about four tunes as 

 long as wide after the first two, whereas in P! even the eleventh segment is still relatively 

 shorter than this and the more proximal ones are mostly less than twice as long as wide. 



P 3 has 7+ segments, probably about 10 and bears a gonad. 



P 6 has 9 segments and measures 3.8 mm. in length. All the segments are very 

 elongated. 



Localities. Siboga station 211; east of Saleyer (south of Celebes) (lat. 540'42" 

 S., long. 12045'30" E.); 1158 meters; coarse gray mud, with the superficial layer more 

 fluid and brown; September 25, 1899 [A. H. Clark, 1912, 1918] (1, Amsterdam M.). 

 Type locality. 



Challenger station 218; north of New Guinea Gat. 233' S., long. 144 04' E.); 1956 

 meters; temperature 2.44 C.; blue mud; March 1, 1875 [P. H. Carpenter, 1888; A. H. 

 Clark, 1913, 1918] (1, B.M.). 



Remarks. P. H. Carpenter's figure of the specimen of "Antedon alternata" dredged 

 at Challenger station 218 shows that it belongs to a species of Fariometra, and it seems to 

 agree in its characters with F. io. 



In 1912 I described a new species which I called Trichometra delicata, based upon 

 a single specimen which had been dredged by the Siboga at station 211, overlooking the 

 fact that in the year preceding I had described under the same name a very different 

 species which had been taken by the Travailleur in the Atlantic. 



In 1918 the new species from the Siboga collection was redescribed and figured 

 under the name of Nepiometra io. 



FARIOMETRA OBSCCRA (A. H. Clark) 



[See vol. 1, pt. 1, fig. 222, p. 243] 



Trichometra obscura A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 149 (description; 

 717'30" N., 76 54' E., 430 fms.) ; Crinoids of the Indian Ocean, 1912, p. 240 (synonymy; de- 

 tailed description; locality), fig. 45, p. 240. 



Nepiometra obscura A. H. CLARK, Journ. Washington Acad. Sci.,-vol. 7, No. 5, 1917, p. 130 (listed); 

 Unstalked crinoids of the Szftoffo-Exped., 1918, p. 245 (in key; range; references). 



Diagnostic features. The single known specimen is of large size, with the centro- 

 dorsal measuring 3.5 mm. in basal diameter by 3 mm. in height; there are conspicuous 



556-62267 18 



