i'5 



a 2 The longest proximal cirrus segments are not longer than the diameter of 

 their clistal ends 



b 1 cirrus segments subequal, mostly about as long as broad, the outer with 

 minute dorsal tubercles; 10 — 30 (usually 20) arms (southern Japan 



and the Liu Kiu Islands) albopurpurca 



b 2 outer cirrus segments broader than long and bearing small, but pro- 

 minent, dorsal spines 



c 1 19 — 29 arms; IIIBr series present; outer edges of the segments 

 of P a with prominent spines at the prismatic angles (K i and 



LesserSunda Islands) manca 



c 3 14 — 18 arms; no IIIBr series; outer edges of the segments of P„ 



with small spines at the prismatic angles (Persian Gul f) . . sohtta 



1. Cyllometra gracilis A. H. Clark. 



A. H. Clark. Arm. and Mag. Nat. Hist., series 8, vol. 10, 19 12, p. 35. 

 Stat. 49a. 8° 23.5 S., H9°4'.6E. Sapéh Strait. 69 Metres. 14 Ex. 



The centrodorsal is discoidal with a flat or slightly concave dorsal pole 2.0 mm. in 

 diameter; the cirrus sockets are arranged in one and a partial' second marginal row. 



The cirri are XXIII, 25 — 30, 21 mm. long: the first segment is short, the second about 

 twice as long (one third to one half again as broad as long), the third slightly longer than 

 broad, the fourth slightly longer than the'third, the fifth nearly as long as the sixth; the sixth- 

 ninth or -tenth are about twice as long as the proximal diameter; the following gradually 

 decrease in length so that the last twelve before the penultimate are subequal, slightly longer 

 than broad. The cirri as a whole are long and unusually slender; owing to the crowded 

 condition of the cirri on the centrodorsal the first segment of each cirrus is sharply flattened 

 laterally against those of the cirri on either side ; the distal dorsal edge of the fourth and 

 following segments is slightly swollen, this after the seventh becoming a trio of dorsal spines, 

 a central larger and two smaller lateral ; the central projects more dorsally than the other two, 

 but does not extend so far distally ; all three are very small ; on the last twelve to fifteen 

 segments before the penultimate the lateral spines disappear and the median becomes slightly 

 more prominent, occurring as a single submedian tubercle, directed obliquely forward ; all the 

 dorsal processes are small and inconspicuous. 



The radials project very slightly beyond the centrodorsal in the median line, but extend 

 well up in the angles of the calyx entirely and widely separating the bases of the IBr^ the 

 division series resemble those of the other species of the genus. 



In the larger specimens the arms are from 26 to 28 in number, and about 50 mm. 

 long; the arrangement of the arms on the rays is 2, 1, 1, 2; IIIBr series appear always to be 

 present, at least on a minority of the rays, and are always external. 



The long distal cirrus segments which bear dorsal processes so slight as scarcely to be 

 noticeable indicate that this species is most closely related to the Japanese C. albopurpurea. 



