On the PhyUostomatous Genera Mimon and Tonatia. 53 



they are quite blunt, some with almost spherical crowns and 

 with the base slightly but more or less distinctly constricted ; 

 they measure only about 1^ millim. 



The longest branch iostegal rays, of whicli several lie 

 scattered in various directions, measure about 2-5 millim. in 

 length and 2 in widt'.i ; they are therefore comparatively 

 slender. The right ventral ^n, pressed close to the origin of 

 the anal, is well jjreserved and contains 14 rays, the longest 

 of whicli measure 27 millim. The depth of the dorsal fin iu 

 front is o3 millim. 



To sum up on the systematic affinities of BenedeniaSj from 

 the evidence which we now possess, it may be said that that 

 genus agrees most nearly in form and lepidosis witli Eary- 

 notus, in dentition with Mesolepis, whilst in the more slender 

 branchiostegal ravs it differs markedly from both, as well as 

 from all Platysomidai and Pala^oniscidie figured by Dr.Traquair 

 or of which 1 have been able to examine speciinens. 



IX. — JSotes on the PhyUostoniatoiis Genera Mimon and 

 Tonatia. By Oldfield Thomas. 



Mr. Alpiionse Robert has sent from Ypanema, Sao Paulo, 

 a number of interesting leaf-nosed bats, and in working them 

 out the following points have appeared and may be of service 

 to students of the group. 



Mimon Bennettii, Gray. 



This excessively rare bat has hitherto only been known, so 

 far as records are given, from the deteriorated type specimen, 

 no. 7 a in the British Museum, received before 1838. That 

 specimen was without locality, and it is therefore of import- 

 ance to record that Mr. Robert has found the species at 

 Ypanema, whence he has sent half a dozen skins which agree 

 closely in all essential characters with the type. Like it 

 they have only two lower premolars, a point about which 

 Dobson expressed some doubt. 



Tonatia. 



Dr. Allen * has stated that this name, based on Vampyrus 

 bidens, Spix, antedates and invalidates my Vampyressa of 

 1900. But the latter was founded, not on Vampyrus bidens, 

 Bpix, but on Vampyrops bidens, Dobson, a bat belonging to 



* Vr. Biol. Soc. Wash. xiv. p. 184 (1901). 



