A MONOGRAPH OF THE EXISTING CRINOIDS 



307 



The two specimens from the Andaman Islands are similar to those from south 

 of Ceylon. One has 14 arms and 26 cirrus segments, and the other has 15 arms and 

 22 or 23 cirrus segments. 



Of the three specimens labeled India one has 20 arms about 65 mm. long; of the 

 10 IIBr series, nine are 4(3+4) and one is 2. Another has 12 arms 25 mm. long; there 

 are 15-18 cirrus segments of which the fifth or sixth and following bear dorsal spines. 

 The third is medium sized. 



Of the 10 specimens labeled ?India, which are probably from Ceylon, 6 are of 

 medium size and 4 are very small. One of the latter has 10 arms 15 mm. long; the 

 cirri are XIV, the longest with 17 segments of which the ninth and following bear 

 dorsal spines, the shorter with 12 segments none of which bear dorsal spines. Another 

 also has 10 arms; the longest cirri are 10 mm. long and are composed of 22 segments, 

 dorsal spines being developed from the seventh segment onward; the smallest cirri are 

 2.5 mm. long with nine segments, quite without dorsal spines and exactly resembling 

 the cirri of young examples of Antedon bifida. A third has 12 arms 25 mm. long. 



Abnormal specimen. In a specimen from south of Ceylon the centrodorsal and 

 division series are of normal size and shape. One cirrus remains which tapers to a 

 point at the seventeenth segment; no dorsal spines are developed. The 19 arms, which 

 are only 17 mm. long, are of normal size basally but rapidly taper to a point beyond 

 which they are continued for a short distance in a slender and soft uncalcified process. 

 The lower pinnules taper very rapidly for the first five or six segments, from that point 

 onward being very slender and hairlike with little or no lime in their composition. 

 Beyond the arm bases the pinnules are exceedingly slender with never more than the 

 first or first two segments of normal size, usually with none, and commonly with traces 

 of calcareous deposits showing segmentation, though often quite without any. With 

 the reduction of the calcareous material in the pinnules comes a reduction in the 

 pinnule sockets, the noncalcareous pinnules in the outer portion of the arm not being 

 accompanied by any modification in the outer edge of the brachials whatever. Most 

 of the arms of this specimen have been broken off and repaired at the syzygy between 

 the third and fourth brachials. 



A marked shortening of the arms, which then taper abruptly, is occasionally 

 noticed in multibrachiate comatulids, though it does not reach anything like the extent 

 seen in this individual. Instances are seen in the specimen of Capillaster macrobrachius 

 collected by the Siboga (see Part 3, p. 159, and compare figs. 26 and 25, pi. 8), and in 

 the specimens of Himerometra robustipinna from Ceylon (recorded by Reicheiisperger 

 as H. kraepelini; see page 199) and Akyab, Burma (the type of Hartlaub's Antedon 

 kraepelini; see page 198). 



Parasite. Two of the specimens from Palk Strait are parasitized by small mol- 



lusks of the genus Sabinetta, which are attached to the cirri near the base (see Part 2, 



p. 648). 



Localities. South Male, Maldive Islands; Prof. J. Stanley Gardiner [A. H. Clark, 



1929] (2, B.M.) 



Ceylon; M. Reynaud, ChevreUe expedition, 1829 [J. Muller, 1846, 1849; Dujardm 

 and Hupe, 1862; P. H. Carpenter, 1879, 1883, 1888; Bell, 1882; Hartlaub, 1891; 

 A. H. Clark, 1907, 1909, 1911, 1912] (1, P.M.). 



Ceylon [Bell, 1887]. 



