96 Memoirs of the Indian Museum. [Voi.. II, 



There is unfortunately some confusion as to the species of Megalasma which 

 occur in Indian seas. In 1894 Weltner described a form to which he gave the 

 name Megalasma carino-dentatum. In preparing his diagno^s he had before him a 

 single specimen from the ''Investigator" collections. The specimen was returned 

 to the Indian Museum but was apparently overlooked when the collection of which 

 it formed a part was unpacked. I have been unable to trace it and have little doubt 

 that it has perished. Pilsbry has recently (1907) suggested that this specimen, which 

 it is impossible any longer to re-examine, was an abnormal one. 



A second form was described by myself in 1906 as Megalasma striatum subsp. 

 minus and by Hoek in 1907 as Megalasma lineatum. Hoek, after seeing the figure 

 of my subspecies in the ''Investigator" Illustrations, acknowledged that M. lineatum 

 was a synonym, and Pilsbry has recently redescribed the form, showing that it should 

 rank as a distinct species. M : minus may therefore be considered a well established 

 species, if it is distinct from M . carino-dentatum. The distinctive characters of the 

 latter were its reduced terga and toothed carina. I have examined over sixty 

 specimens of M. minus and have found none with a toothed carina; but the relative 

 size of the tergum varies considerably in this series and a tooth occurs on the carina 

 on a small proportion of individuals of some species of Pœcilasma {e.g., P. minutum, 

 see fig. 5, pi. vii). 



For these reasons, in the absence of a specimen of M. carino-dentatum, I think it 

 will be best to regard the species as a doubtful one. 



Megalasma carino-dentatum , Weltner {species dubia). 



M. carino-dentatum, Weltner, Sitz. Ber. Ges. Natur/. Freunde, 1894, p. 84. 



Exhibiting the characters of the genus; the carina with a distinct tooth near 

 its upper extremity ; terga reduced. 



Attached to the filamentous spicules of the Hexactinellid sponge Hyalonema 

 masoni. Bay of Bengal at a great depth. 



Megalasma minus, Annandale. 



M. striatum subsp. minus, Annandale, Ann. Mag.' Nat. Hist. (7), vol. xvii, p. 399 



(1906); Illustr. Zool. ''Investigator," Crust. Ent., pi. i, fig. 8 (1907); M. 



minus, Pilsbry, Proc. A. Nat. Sei. Philadelphia , lix, p. 409, figs, i, 3, 4, 6 



(1907). 



M. lineatum, Hoek, Siboga-Exped., Mon. xxxia, Cirr. Fed., p. 31, pi. iv, figs. 



1—8(1907). 

 CAPITUI.UM. — Carina reaching posterior angle of the tergum above, where it 

 is distinctly pointed, with a regular series of /\- shaped ridges on the dorsal surface ; 

 the lateral surfaces strongly ridged vertically, the lateral basal margin frequently 

 irregular. Tergum subtriangular, the posterior angle narrowly truncate or irregularly 

 sinuous ; the occludent margin barely ^ as long as scutal margin ; scutal and superior 

 margins equal; a distinct internal tooth near the scutal margin a short distance 



