28 PR0CEEDIXG8 OF THE NATIONAL MUSEUM. vol.40. 



DICHROMETRA FLAGELLATA (J. Miiller). 



Alecto flagellata J. Muller, Archiv fur Naturgesck., 1841, Heft 1, p. 145. 

 Antedon flagellata Ludwig, Senck. naturforsch. Ges., vol. 21,1899, Heft 4, p. 538. 

 Dichrometra flagellata A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, 

 p. 13. 



Localities. — Reef opposite the harbor of Lamu; Zanzibar. 

 Depth. — Littoral. 



This species ranges eastward to Singapore, New Guinea, and 

 Amboina. 



Family COLOBOMETRIDyE. 



Germs CENOMETRA A. H. Clark. 



CENOMETRA EMENDATRIX (Bell). 



Antedon emmdatrix Bell, Ann. and Mag. Nat. Hist., (6) vol. 9, 1892, p. 428, pi. 18. 

 Antedon spicata Bell, Trans. Linn. Soc. (Zool.), (2), vol. 13, 1909, pt. 1, p. 20. 



Description. — Centrodorsal low hemispherical or thick discoidal, 

 the sides strongly inclined, about 4 mm. in diameter; dorsal pole very 

 slightly concave, small; cirrus sockets arranged in two crowded and 

 irregular rows. 



Cirri XVIII, 28-33 (usually nearer the latter), comparatively slender, 

 15 mm. to 20 mm. long; first cirrus segment short, the following 

 gradually increasing in length to the fourth which, with the follow- 

 ing, is about half again as broad as long; the penultimate and ante- 

 penultimate segments are about as long as broad; after the eighth the 

 distal dorsal edge begins to project slightly, this projection after the 

 sixteenth becoming a pair of small, though prominent, dorsal spines 

 situated close together, one on either side of the median line ; on the 

 antepenultimate segment only a single median small spine is found; 

 in the terminal third of the cirrus the paired dorsal spines, which at 

 first were near the distal dorsal edge of the segments, have moved to 

 a median position; opposing spine long and prominent, reaching 

 somewhat over half the diameter of the penultimate segment in 

 height, arising from nearly or quite the entire dorsal surface of that 

 segment, the apex sub terminal or median; terminal claw about as 

 long as the penultimate segment, rather stout basally, but abruptly 

 decurved and comparatively slender in its distal half. 



Radials four or five times as broad as long, their interior angles 

 slightly separated; IBr x oblong, twice as broad as long; IBr 2 (axil- 

 lary) nearly or quite as long as broad, pentagonal, with a slight 

 transverse median constriction; IIBr 2, resembling the IBr; the divi- 

 sion series and first brachials bear comparatively short, though thick, 

 ventrolateral processes; the division series are well separated. 



Seventeen arms 90 mm. long, comparatively slender and delicate, 

 increasing slightly in width to the twelfth or fourteenth brachials, 

 then gradually tapering distally; first two brachials subequal, wedge- 

 shaped, about twice as broad as long exteriorly, the first interiorly 



