327 



the rostral région ; anterior margin broadly rounded, ventral margin slightly arcuate, posterior 

 end sLibtruncate, anterior dorsal margin arcuate, posterior oblique ; umbones full subcentral, 

 prosogyrate; sculpture consisting of fine granules irregularly arranged ail over except in umbonal 

 area, a few low concentric threads also présent near ventral margin of shell ; hinge normal. Shell 

 white, nacre slightly pearly. 



Measurements of Holotype : — Length 17.5 mm., height 12.6 mm., diameter 10.7 mm. 



Habitat : The unique Holotype of this new species was brought up in a trawl at St. 306 

 (8°27''S., i22°54'.5E., 247 mètres). 



Remarks : — The elongate-ovate, inflated and rostrate shell of P. (C) gloriosa distinguish 

 it from other known species of the genus. 



3. Poromya [Cetoconchd) exi7nia sp. nov. (Plate VII, figs. 31, 32). 



P . (C) eximia is closely allied to P. (C) gloriosa Prashad described above, but the 

 shell of this species is very much deeper, much more inflated, the rostral part shorter and 

 broader, umbones very full and prominent, ventral margin much more arcuate and the sculpture 

 consisting of better developed granules and stronger concentric striae. The shell of this new 

 species is thicker than that of P . (C) gloriosa and is of a pale straw colour. 



Measurements of Holotype: — Length 17.5 mm., height 15.4mm., diameter 15. i mm. 



Habitat: — The unique Holotype was brought up in a trawl at St. 314 (7° 36' S., 

 1 17° 30^.8 E., 694 mètres). 



4. Poromya [Cetoconcha] bzitoni sp. nov. (Plate VII, figs. 33, 34). 



The following is a description of this new species : — Species of a small size ; shell 

 ovate, inequilateral, inequivalve, slightly rostrate, slightly convex; acuminately rounded in front, 

 subtruncated behind, ventral margin arcuate, anterior dorsal margin shorter than posterior, 

 regularly curved, posterior somewhat obliquely concave; umbones moderately prominent, full, 

 situated in front of centre, curved backwards and inwards; sculpture consisting of minute elevated 

 granules distributed regularly over entire surface except central part of shells. Shell of a pale 

 straw colour, nacre pearly white. 



Measurements of Holotype: — Length 7 mm., height 5.9 mm., diameter 4.8 mm. 



Habitat : — The Holotype was dredged between the islands of Wowoni and Buton in 

 the northern entrance of Buton Strait (St. 204). A shell from St. 102 (6° 4^1 N., 120° 44' E., 

 535 mètres) also appears to belong to the same species. 



Family Cuspidariidae. 

 Genus Cuspidaria Nardo. 



1840. Cuspidaria Nardo, Rev. Zoo]., p. 30. 



1847. Neaera Gray, Proc. Zool. Soc. London, p. 192. 



1885. Neaera Smith, "Challenger" Lamellibranchia, p. 35. 



1886. Cuspidaria Dali, Bull. Mus. Comp. Zool. Harvard, XII, p. 292. 



