A MONOGRAPH OF THE EXISTING CRINOID8 431 



Phanogenia gracilis A. H. Clark, Proc. U. S. Nat. Mus., vol. 35, 1908, p. 124 (listed); Smiths. 



Miscell. Coll., vol. 52, pt. 2, 1908, p. 203 (arm Ktructure); Proc. U. S. Nat. Mus., vol. 36, 1909, 



p. 392 (arms compared with tliose of C. minima). 

 Actinomeira tridistichala (B. M., MS.) A. H. Clark, Crinoids of the Indian Ocean, 1912, p. 84 



(Bell, MS. —Comaster gracilis; Macclesfield Bank, 30 fathoms); Smiths. Miscell. Coll., vol. 61, 



No. 15, 1913, p. 79 (same). 

 Actinometra slellata (B. M., MS.) A. H. Clark, Smiths. Miscell. Coll., vol. 61, No. 15, 1913, p. 78 



(Fiji). 



Diagnostic features. — In general resembling multifida but smaller and of a much 

 more slender build, the division series being narrow and widely separated. The arms 

 average 56 in number. The division series and arms have a conspicuous dark narrow 

 mediodorsal stripe. The centrodorsal is greatly reduced and stellate. 



Description oj the type specimen. — The centrodorsal is small and flat with a 

 central concavity, pentagonal with slightly concave sides, scarcely raised above the 

 dorsal surface of the radials. 



The entire dorsal surface of the radials is visible. The IBri are oblong, about 

 3 times as broad as long, and entirely free laterally. The IBrj (axillaries) are broadly 

 pentagonal, with the lateral borders almost or quite as long as those of the IBri 

 and making with them a straight line or a slight angle; the anterior sides are slightly 

 concave and the anterior angle is broader than a right angle with a rounded apex. 

 The IIBr series are 4 (3+4) and the following series are all 2 (1 +2). The division 

 series are narrow and widely separated, and the arms divide not more than four 

 times. 



The arms are 48 in number, about 160 mm. long, very slender, and becoming 

 extraordinarily attenuated in the distal portion. The brachials are moderately long. 

 The first and second brachials are oblong, broader than long, and are united by 

 syzygy. The next 3 or 4 are similar, and the remainder are short wedge-shaped, 

 with somewhat projecting distal edges which are armed with fine spines. 



Syzj-gics occur between brachials 1+2, 10+11, or 11+12, and thence at 

 intervals of 3 muscular articulations. 



The disk is 15 mm. in diameter, somewhat incised, and beset with fine calcareous 

 concretions. The mouth is almost central. 



Pd is about 13 mm. long and is composed of numerous segments, of which the 

 distal are somewhat longer than broad ; the comb is quite inconspicuously developed 

 and is rolled into a small knob. Pi is shorter, and the 3 following pinnules are much 

 shorter. The succeeding pinnules gradually increase in length, reaching 10 mm. 

 distally. The lower pinnules are slender. The segments of the distal pinnules are 

 very spiny. 



The color in alcohol is light grayish brown, the division series and arms with 3 

 longitudinal lines of dark brown, 1 mediodorsal and the other 2 dorsolateral; the last 

 are only slightly evident on the arms. On the arms hght-grayish-brown and dark- 

 browTi patches alternate. The disk is dark brown. 



Notes. — In the specimen from the Maldives there are a few VBr series. 



The specimen from the Andamans is small and resembles those from Singapore 

 in the Copenhagen Museum, with which it was compared directly. 



