A MONOGRAPH OF THE EXISTING CRINOIDS 1.57 



has a large pentagonal peristome but is much incised, and the anal tube appears to 

 be quite at its margin, so far as one can judge from the mutiliated condition of the 

 specimen. The sacculi do not appear to occur on the disk, but they are well developed 

 on the arms, and especially so on the pinnule ambulacra. 



In the specimen from Siboga station 305 the dorsal pole of the centrodorsal is flat, 

 2 mm. in diameter. The cirri are XV, 31, about 15 mm. long. The fifth-seventh 

 segments are about as long as their distal width. The sLxth and following segments 

 have prominent paired dorsal spines which at first are widely separated but distally 

 approach each other and merge into a single spine on the last two segments before the 

 penultimate. The 19 arms are 60 mm. long, and are arranged on the five postradial 

 series as follows: 4(1+3), 4(1+3), 3(1+2), 6(2, 1, 1, 2), 2. The IIIBr series are all 

 externally developed. Pj is 11 mm. long and is composed of 16 segments. 



Of the two specimens from ?Kurrachi one has 16 and the other 18 arms. 



The specimen from Investigator station 291 was described by the author as a new 

 species under the name of Cyllometra soluta. The centrodorsal is thin discoidal with 

 the bare polar area 2 mm. in diameter and the cirri arranged in a single marginal row. 

 The cirri are XVI, 21-28, from 11 to 13 mm. long. The fourth or fifth and following 

 segments are subequal, about as long as broad. The third or fourth and following seg- 

 ments have produced distal ends which soon transform into prominent paired dorsal 

 spines, becoming single median dorsal spines on the terminal five or six. The structure 

 of the division series and arms resembles that in C. manca and C. albopurpurea. The 

 14-18 arms are 55 mm. long. P^ is absent. P, is small and very slender, 3 mm. long 

 with about 12 segments. Pj is the largest and the longest pinnule on the arm, 1 1 mm. 

 long with 17 segments of which the first is not so long as broad, the third is twice as 

 long as broad, and the remainder are about three times as long as broad. The pinnule 

 is much more slender than the corresponding pinnule in related forms, and is nearly 

 smooth, the distal edges of the segments in the terminal portion projecting only very 

 slightly. Pa is 7 mm. long, similar to Pj but very slender, the segments distally pro- 

 portionately somewhat longer. The pinnules following are more slender still, about 

 5 mm. long with 15 segments, and flexible, gradually decreasing in length to 4 mm. 

 and increasing agam to 8 mm. distally. The color in alcohol is flesh color, with a few 

 narrow bands dorsally and large blotches ventrally of purple. 



Abnormal specimens. — In the specimen from off Hondo, Japan, described as 

 Cyllometra avomala one of the seven IIBr series is 2 and the other six consist of 4 ossi- 

 cles each united in two synarthrial pairs, the second ossicle in each case bearing a 

 pinnule. There are also present three IIIBr series of two ossicles each, of wiiich the 

 second is not an axillary (see p. 145). 



In a specimen with 21 arms from lat. 35° 11' N., long. 138° 43' E., the first syzyg- 

 ial pair is repeated, so that there are syzygies between brachials 3+4 and 5 + 6; the 

 epizygals of both of these syzygial pairs are without pinnules. 



In a specimen from Mortensen's station 10 one of the IIBr series is composed of 

 3 ossicles, all united by synarthry. 



In another specimen from Mortensen's station 10 one of the IIBr series is 4(3+4), 

 with a pinnule on the second clement. 



In a third specimen from Mortensen's station 10 the third brachial on the left 

 branch from the right posterior postradial series bears externally a normal arm and 



