A. H. CLARK : THE CRINOIDS OF THE INDIAN OCEAN. 207 



IBr., roughly rhombic with the lateral angles truncated and all the sides concave ; 

 the lateral edges are nearly as long as those of the IBr , ; the proximal and distal 

 edges are everted, the proximal resembhng the distal edge of the IBr ,, the distal 

 with a more regular finely spinous margin ; the ossicles of the IBr series are in 

 close lateral apposition and are narrowly ''wall-sided " ; their lateral edges are 

 perfectly plain, without spines or tubercles. 



Ten arms, all broken off at the first syzygy, between the third and fourth 

 brachials. In shape the brachials resemble those of the other ten-armed species 

 of the genus ; they are perfectly smooth , with no trace of spines or of median 

 carination ; the proximal and distal edges are slightly thickened and everted , 

 with a few small spines or tubercles. 



Locality. — " Investigator " Station 218 ; Maldive Islamls ; 2\0 fathoms. — One 

 specimen, very fragmentary. 



Remarks. — This new species is related to Th. hawaiiensis and to Th. hirsuta ; 

 from the former it differs in the much smaller centrodorsal , in the smaller number 

 of cirrus segments, of which the proximal are much longer, in the shorter ossicles 

 of the IBr series, which are in close lateral contact without intervening radial 

 water pores, and in the eversion of the edges of the ossicles of the IBr series 

 and of the earlier brachials, these in Th. hawaiiensis being armed with large 

 coarse blunt scattered spines, though not as a whole turned outward; there are 

 no spines on the dorsal surface of the ossicles in Th. marqinata such as occur, 

 though sparingly, in Th. hawaiiensis. From Th. hirsuta this new form differs 

 in the very large and coarse instead of fine tubercles on the dorsal pole of the 

 centrodorsal, in the smoothness of the wedge-shaped area separating the columns 

 of cirrus sockets proximally, in the fewer cirrus segments, of which the longest 

 are somewhat shorter, and in the much less and more coarsely spinous edges to 

 the ossicles, as well as in the entire absence of a median carination and of spines 

 on the dorsal surface of the ossicles of the IBr series and lower brachials. 



THALASSOMETRA PUBESCENS. 



Antedon jmbescens 1907. A. H. Clark, Proc. U. S. Nat. Mus., vol. 33, p. 139. 

 Thalassometra puhescens 1907. A H. Clark, Smiths. Misceil. Coll. (Quarterly 



Issue), vol. 50, part 3, p. 360. 



Habitat. — Southern Japan. 



Depth. — 440 fathoms. 



THALASSOMETRA PERGRACILIS. 



Antedon gracilis 1888. P. H. Carpenter, "Challenger" Reports, vol. 62, 



Zoology, p. 107, pi. xii, figs. 3-5; pi. xv, figs. 1-4. 

 Thalassometra pergracilis 1907. A. H. Clark, Smiths. Misceil. Coll. (Quarterly 



Issue), vol. 50, part 3, p. 360. 



