PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 109 



The color in alcohol is brownish yellow. 



Locality.— Unknown [A. H. Clark, 1908, 1909, 1912, 1918] (1, CM.). 



MASTIGOMETRA MICROPODA A. H. Clark 



Figure 8 



[See also vol. 1, pt. 2, figs. 570, 571, p. 298] 



Mastigomelra micropoda A. H. Clark, Proc. U.S. Nat. Mus., vol. 36, 1909, p. 649 (description; ?India) ; 

 Vid. Medd. Nat. Foren. K0benhavn, 1909, p. 128 (closely related to M. flagellifera and to the 

 species of Antedon; Indian Ocean and Ceylon); Crinoids of the Indian Ocean, 1912, p. 227 (de- 

 tailed description; ?India; Ceylon); fig. 42, p. 228. — 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. 198 (in key; range), p. 200 (references). 



Diagnostic features. — The L-XC cirri have about 16 segments, of which the si.xth 

 and following are about as long as broad; Pi is 15 mm. and P2 is 9 mm. long. 



The arms are about 80 mm. and the cu'ri about 10 mm. in length in the holotype. 



Description. — The centrodorsal is low hemispherical, 4 mm. in diameter at the 

 base, the polar area slightly convex, or flattened; the cirrus sockets are very niunerous 

 and are arranged in four or five closely crowded alternating rows. 



Cirri L-XC, 16, about 10 mm. long; the first two segments are short, rather over 

 twice as broad as long, the third is from as long as broad to a third again as long as 

 broad, and the fourth and fifth are slightly longer; the following segments are subequal, 

 about as long as broad; the third to sixth segments are slightly constricted centrally, 

 the remaining segments having the ventral surface practically straight and the 

 dorsal with a slight median concavity. The cirri become somewhat compressed laterally 

 in the distal two thirds and therefore appear very slightly broader in lateral view. The 

 opposing spine is represented by a slight terminally situated tubercle which may be 

 obsolete. 



Scattered calcareous granules are present along the ambidacral grooves of the disk 

 and perisomic interradials may be present between the IBrj as in Antedon bifida. 



The distal borders of the radials are even with the edge of the centrodorsal. The 

 IBr, are very short, five or six times as broad as long, of uniform height, not quite in 

 apposition basally, the lateral edges of adjacent plates diverging distally. The IBro 

 are triangidar, about half again as broad as long, the distal angle somewhat produced, 

 the proxunal border as long as the proximal border of the IBr,. 



The 10 arms are probably about SO mm. long, and resemble in structiu-e those of 

 M. flagellifera. 



The distal intersyzj'gial interval is 3 muscular articulations. 



Pi is 15 mm. long, much stouter basally than the succeeding, though tapering 

 evenly to an exceedingly slender and delicate flagellate tip. P2 is 9 mm. long. The 

 foUowing pinnules graduaflj' decrease in length. The pinnules are of the same pro- 

 portions and structiu-e as are those of M. flagellifera. 



The color in alcohol is brownish white. 



Localities.— ?India. [A. H. Clark, 1909, 1912, 1918] (4, U.S.N.M., 35655 [17H], 

 35656 [16H]; the holot.>TDe, I.M.). T^qie locaHty. 



OflF the Colombo Light House, Cevlon; 48 meters [A. H. Clark, 1909, 1912, 1918] 

 (1, LM.). 



Remarks. — The five kno^\ai specimens of this species were all collected by the 

 Investigator; only one of them bears a definite localit}'. 



