A. H. CLARK : THE CRINOIDS OF THE INDIAN OCEAN. 195 



Pinnules much longer than those of A. anthus, and more slender with propor- 

 tionately longer segments, those in the terminal portion being three times as 

 long as broad or even longer, whereas in A. anthus they do not exceed twice the 

 breadth; P, is 7 mm. long with twelve segments; P., is similar, 7*5 mm. long; Pg 

 is slightly stouter, 8 mm. long ; P5 is 9 mm. long ; the distal pinnules are 13 mm. 

 long. 



The colour in spirits is brownish white. 



Locality.— /Sa/m? Bank (10° 30' S. lat. , 125° E. long.) — One specimen. 



Remarks. — It is interesting to note that this species represents the smaller 

 and more slender component of a specific pair inhabiting a single locality (the 

 larger and stouter component being Astewmetra mirifica) just as A. anthus is 

 the smaller and more slender component of the anthus-macropoda pair of south- 

 ern Japan ; and that, while both species of the latter pair have more than ten 

 arms, both species of the acerba-'mirifica pair have ten arms only. 



I have examined some additional specimens of this species from the same 

 locality which are preserved in the British Museum. 



ASTEROMETRA LEPIDA. 



Asterometra lepida 1908. A. H. Clark, Proc. Biol. Soc. Washington, vol. 21, 

 p. 229. 



Habitat. — Straits of Formosa (Taiwan). 

 Depth. — 35 fathoms. 



Genus THALASSOMETRA 



Thalassometra 1907. A. H. Clark, Smiths. Miscell. Coll. (Quarterly Issue), vol. 50, 

 part 3, p. 359 (Antedon villosa A. H. Clark, 1907). 



THALASSOMETRA ANNANDALEI. 



Crotalometra annandaki 1909. A. H. Clark, Proc. U. S. Nat. Mus., vol. 36, 



p. 642. 

 Thalassometra annandaki 1911. A. H. Clark, Proc. U. S. Nat. Mus., vol. 39. p. 

 551. 



Description. — Centrodorsal columnar, the tip truncated conical as in Astero- 

 metra 5 mm. long by about 5 mm. broad at the base ; cirrus sockets arranged 

 in ten columns of usually three each, the columns of adjacent radial areas being 

 closely crowded and more or less alternating, the two columns of each radial area 

 being separated by a slightly concave median area of about half their width ; 

 polar area with five more or less marked interradial ridges which terminate in 

 five small tubercles about the apex. 



Cirri comparatively slender, XXX, 62-79, 65 mm. long; first three segments 

 approximately equal, short, about twice as broad as long, the following gradually 



