420 Mr. G. A. Boulenger on 



sexual maturity. He also describes an individual which, 

 though internally it exhibited fully developed male sexual 

 organs, as far as its exterior was concerned bore quite the 

 character of a female, even possessing, indeed, rudiments of 

 brood-lamellae. 



I incline towards the view that Isopods were originally 

 altogether hermaphrodite. Such conditions, however, per- 

 sisted only in parasitic forms (Cymothoidas), for which 

 hermaphroditism must be universally advantageous. In the 

 case of free-living forms this state of affairs disappeared. In 

 them we find that only scattered and scanty hermaphrodite 

 remnants or rudiments are preserved. 



LXI. — A new Genus of AgJossal BatracMans. 

 By G. A. BouLENGEE, F.R.S. 



Among the rich herpetological collections made by Stuhlmann 

 in East Africa the frog described by Tornier as Xenopus 

 Boettgeri (Thierw. Ost-Afr., Kept. Arnph. p. 163, fig., 1896) 

 is of exceptional interest in adding a second genus to the 

 Dactylethridge. As Tornier has not realized the systematic 

 importance of the characters which differentiate the new 

 species from Xenopus Jcevis and its allies, it is thought desir- 

 able to emphasize it by raising Xenopus Boettgeri to 

 generic rank under the name of HymenocMrus Boettgeri. 

 The principal characters that distinguish HymenocMrus from 

 Xenopus are, so far as can be judged from Tornier's description 

 and figure, the half-webbed fingers, the incompletely webbed 

 toes, the third of which considerably exceeds the fourth in 

 length, and, above all, the absence of lines of sensory muci- 

 ferous canals on the body. No doubt a careful examination 

 of the type specimen, unfortunately still unique, would reveal 

 further differences, and the Eontgen rays might be usefully 

 applied to obtain some information on the osteological 

 characters. 



LXI I. — Descriptions of Two new Frogs obtained in Mada- 

 gascar by Dr. Forsyth Major. By G. A. BoULENGER, F.R.S. 



Mantidactylus Majori, 



Closely allied to M. curtus, Blgr., but snout much longer, 

 acutely pointed, and very strongly projecting beyond the 

 mouth. Vomerine teeth in two small, oblique, oval groups 

 close together behind the level of the choanse. Head longer 



