84 Memoirs of the Indian Museum. [Voi.. II ^ 



There can be little doubt that the degeneracy of these rami brings the subgenus 

 into close relationship with the Alepadinse, and it is noteworthy that the mandibles of 

 the species of both subgenera show a certain approximation in form to those of the 

 species of that degenerate subfamily. Degeneracy in the mandibles consists, however, 

 very largely in a reduction in the number of their teeth, and it must be noted that a 

 reduction of the kind takes place occasionally, as an individual peculiarity, in widely 

 separated families. For instance, in some examples of Pœcilasma minutum two 

 of the central teeth fuse together, as a rule only on one mandible ; while in the speci- 

 men of Scalpellum sociahile which was first dissected the large outer tooth of both 

 mandibles had completely disappeared, although in other specimens from the same 

 locality since examined it has been found to be well developed.^ However this may 

 be, it seems clear that the genus Heteralepas {sensu lato) affords a link between the 

 subfamilies Lepadinse and Alepadinse. It may be necessary later, however, as Pilsbry 

 points out, to separate Paralepas from Heteralepas as a distinct genus. 



Only two species of Heteralepas have been as yet recorded from Indian seas, one 

 representing each subgenus. They are — 



Heteralepas {Paralepas) xenophorce , mihi, 

 and 



Heteralepas {Heteralepas) nicobarica, sp. nov. 



Subgenus Parat.Epas, Pilsbry. 



Heteralepas {Paralepas) xenophorœ (Annandale). 



Alepas xenophorœ, Amiandale, Ann. Mag. Nat. Hist. (7), vol. xvii, p. 399 (1906); 

 Illustr. Zool. " Investigator," Crust. Ent., pi. ii, figs. 5, 5a, 5b ; Hoek, Siboga- 

 Exped., Mon. xxxiö, Cirr. Ped., p. 39. 



CapituIvUM subtriangular, pointed at the apex, slightly inflated below the aper- 

 ture (at the base of which there is a distinct constriction), marked with transverse 

 striae. Aperture slit-shaped, with barely protuberant lips, rather less than a third as 

 long as the vertical length of the capitulum. No scuta. 



PEduncIvE stout, irregularly but finely annulated, longer than the capitulum. 



Cirri, etc. — Cirri short and feebly curved, with the pedicel long as compared 

 with the rami. First cirrus widely separated from the second, each of its rami with 

 five distinct joints, of which the proximal joint equals the sum of the others in 

 length; the anterior ramus with a soft, easily broken cylindrical process at its tip; 

 this ramus distinctly broader than the other and longer by one complete joint ; the 

 basal joint of each ramus broadly convex outwards on the posterior margin, the other 

 joints having this margin nearly straight and the anterior margin more or less convex ; 

 each joint of both rami bearing a circle of stout feathered bristles round its distal ex- 

 tremity and each basal joint with a dense fringe of similar bristles running down both 



1 1 have satisfied myself that this is so by re-examining my preparations of the type specimen, and 

 by dissecting several others [see Mem. Asiat. Soc. Bengal, vol. i, p. 78, fig. 2 (1906)]. 



