A MONOGRAPH OF THE EXISTING CRINOIDS 185 



In another specimen in the British Museum from Cargados Carajos in 55 meters 

 the cirri are XVII, 27-28, 14 mm. long, moderately slender. All the segments are 

 subequal, about half again as broad as long. On the sixth or seventh segment a 

 transverse ridge begins to develop which becomes a pan- of small low tubercles on 

 the tenth or twelfth. The 10 arms are 90 mm. long. P a is absent. PI is slender, 

 small, and weak, 5 mm. long with 13 segments. P 2 is the largest pinnule, though 

 it is not especially enlarged. It is slender and distally flagellate, 9 mm. long with 

 18 segments most of which are nearly twice as long as broad. The outer segments 

 have slightly prominent distal edges, and especially distal angles. P 3 is intermediate 

 between P! and P 2 . PI and the following pinnules are small and weak. The distal 

 pinnules are very slender, 9 mm. long. 



Localities. Cargados Carajos; 55 meters; Sea Lark; Prof. J. Stanley Gardiner 

 [A. H. Clark, 1911, 1912, 1913, 1918] (3, B. M.). 



Cargados Carajos; Sea Lark; Prof. J. Stanley Gardiner [A. H. Clark, 1929] (2, 

 B. M.). 



History. Decametra alaudae was first described in a paper by me on the crinoids 

 of the coasts of Africa published in 1911. The description was based on a specimen 

 in the British Museum that had been collected by Prof. J. Stanley Gardiner on the 

 Sea Lark expedition at Cargados Carajos in 30 fathoms. In my memoir on the crin- 

 oids of the Indian Ocean published in 1912 I listed this species and gave the original 

 reference and habitat. In my paper on the crinoids of the British Museum published 

 in 1913 I redescribed this species and gave notes on a second specimen from the type 

 locality. In my report on the unstalked crinoids of the Siboga expedition this species 

 was included in the key to the species of the genus Decametra and the habitat was 

 given. In 1929 I recorded two additional specimens from the type locality and gave 

 extensive notes on the larger of the two. 



DECAMETRA TAPROBANES (A. H. Clark) 



PLATE 24, FIGURES 119, 120; PLATE 25, FIGURE 130 

 [See also vol. 1, pt. 2, figs. 486, 487 (pinnule tip), p. 269.] 



Antedon laevissima (part) BELL, in Gardiner, Fauna and geography of the Maldive and Laccadive 

 Archipelagoes, vol. 1, pt. 3, 1902, p. 224 (Fadiffolu, Muhlos, Maldives). 



Cyllometra taprobanes A. H. CLARK, Proc. U. S. Nat. Mus., vol. 36, 1909, p. 641 (off Colombo Light 

 House, Ceylon, 26^ fms.; description). H. L. CLARK, Echinoderm fauna of Australia, 1946, 

 p. 52. 



Decametra taprobanes A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 33 (arms compared with 

 those of D. alaudae); Crinoids of the Indian Ocean, 1912, p. 40 ( = Antedon laevissima Bell, 1902, 

 in part), p. 159 (synonymy; description; localities), fig. 23, p. 159; Smithsonian Misc. Coll., vol. 

 61, No. 15, 1913, p. 36 (published reference to specimens in the B. M.; Fadiffolu, Muhlos, Mal- 

 dives; notes). H. L. CLARK, Spolia Zeylanica, vol. 10, pt. 37, 1915, p. 93 (occurs at Ceylon). 

 A. H. CLARK, Unstalked crinoids of the Siboga-Exped., 1918, p. 117 (in key; range); John Mur- 

 ray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1936, p. 100 (range), p. 103. H. L. CLARK, 

 Echinoderm fauna of Australia, 1946, p. 52. 

 Diagnostic features. The cirri are 12-13 mm. long with 23-29 segments of which 



the three or four outermost are about as long as broad; P 2 is almost twice as long as P 1( 



stouter and stiffer, though not especially enlarged, 8 mm. long with 15-17 segments; 



P 3 is 6 mm. long with 14 segments; the arms are about 80 mm. long. 



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