A MONOGRAPH OF THE EXISTING CRINOIDS 187 



Fadiffolu, Miihlos, Maldives; J. Stanley Gardiner [BeU, 1902; A. H. Clark, 1912, 

 1913] (1, B. M.). 



Muhlos, Maldives; J. Stanley Gardiner [Bell, 1902; A. H. Clark, 1912, 1913] 

 (3, B. M.). 



Investigator; ?India (probably Ceylon) [A. H. Clark, 1912] (1, I. M.). 



Geographical range. Ceylon and the Maldive Islands. 



Bathymetrical range.- From the shore line down to 58 meters. 



History. The first mention of this species was by Prof. F. Jeffrey Bell, who 

 recorded specimens of it from the Maldive Islands under the name of Antedon laevis- 

 sima in 1902. 



The species was first described under the name Cyllometra taprobanes by me in 

 a preliminary paper on the crinoids of the Indian Museum published in 1909. The 

 only locality given in the original description was off Colombo Light House, Ceylon, 

 in 26>2 fathoms. In 1911 I compared the arms of my new species Decametra alaudae 

 with those of Decametra taprobanes and said that the former appears to be most closely 

 related to the latter. In my memoir on the crinoids of the Indian Ocean published 

 in 1912 I redescribed and figured D. taprobanes and identified with it specimens I 

 had examined at the British Museum in 1910 that had been identified as Antedon 

 laevissima by Bell. These specimens had come from the Maldive Islands. I listed 

 specimens from off Colombo Light House, Ceylon, in 26% fathoms; from south of 

 Ceylon in 32 fathoms; from ?India; from Fadiffolu, Muhlos, Maldives; and from 

 Muhlos, Maldives. In my paper on the crinoids of the British Museum published 

 hi 1913 I recorded specimens of Decametra taprobanes from Fadiffolu, Muhlos, Mal- 

 dives, and from Muhlos, Maldives, that had been previously recorded by Bell as 

 Antedon laevissima. In my report on the crinoids of the Siboga expedition published 

 in 1918 I included taprobanes in the key to the species of the genus Decametra, giving 

 as the locality Ceylon. 



DECAMETRA ARABICA A. H. Clark 



Decameira arabica A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 161 (Antedon carinata B. M., 

 MS.; description; Muscat); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 36 (same); Un- 

 stalked crinoids of the Siboga-Exped., 1918, p. 117 (in key; range) ; John Murray Exped. 1933-34, 

 Sci. Reports, vol. 4, No. 4, 1936, p. 100 (range), p. 104. 



Antedon carinata (Brit. Mus. MS.) A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 36. 



Diagnostic features. The cirri are 13 mm. long with 26 or 27 segments of which the 

 proximal are about twice as broad as long and the terminal are about as long as broad; 

 the ninth or tenth and following bear small paired dorsal spines ; P 2 is twice as long as 

 the small and weak PI, slender, though stiffened, with 15 segments most of which are 

 twice as long as broad; P 3 is similar to P 2 but shorter; the arms are 110 mm. long. 



Description. The cirri are XIX, 26-27, 13 mm. long, and are slender. The 

 proximal segments are about twice as broad as long, and the terminal segments are 

 about as long as broad. The ninth or tenth and following segments bear small paired 

 dorsal spines. 



The 10 arms are 110 mm. long and resemble those of the other species of the 

 genus. 



P a is absent. Pt is very small and weak, 4.5 mm. long. P 2 is 9 mm. long and is 

 composed of 15 segments most of which are twice as long as broad with the distal 



