Vertebrate Fossils from Brazil. 135 



bited, the feeble pelvic fins, the opposed small dorsal and 

 anal, and the delicate overlapping cycloid scales. These 

 fossils, however, only indicate a fish about 0*15 m. in 

 length, though the proportions are so similar that it seemB 

 most probable they merely represent the young of the species 

 already described. 



Lepidotus Mawsonij sp. nov. 



Several scales and teeth have already been figured and 

 briefly noticed by Allport and Egerton [loc. cit.) ; and, as the 

 result of Mr. Mawson's researches, the British Museum is now 

 provided with a large series of these detached fragments. 

 The scales are in every respect typical of the genus, and 

 derived from all the principal regions of the body. Some are 

 of very large size measuring no less than 0*04 m. antero- 

 posteriorly j and the majority have a smooth external surface, 

 sometimes irregular, but only rarely showing faint traces 

 of posterior radiating grooves, with a few large posterior 

 crenulations. A most remarkable peculiarity of the scales 

 consists in the enormous thickness of the laminated bony 

 base ; for the greater portion of the base {e. g, in B. M. nos. 

 5534 a, b) not unfrequently becomes swollen into a prominent 

 rounded excrescence, unequalled by any other Lepidoius-scale 

 the present writer has had the opportunity of examining. 

 The associated teeth, presumably referable to the same fish, 

 are notably small in proportion. While many of the scales 

 are as large as those of the great Lepidotus maximus^ the 

 known teeth scarcely attain the dimensions of those of L. 

 Mantelli] and it is very unlikely that if the Brazilian species 

 originally possessed teeth equalling those of L. maximuSj they 

 would hitherto have escaped detection. The latest evidence 

 collected by Mr. Mawson thus appears to confirm Sir Philip 

 Egerton's early suspicion that the Bahia Lepidotus is distinct 

 from all other described species ; and the fossils are quite as 

 satisfactory as those upon which many other species of the 

 genus are founded. The fish may therefore appropriately 

 receive the name of Lepidotus Mawsoni. 



Acrodus nitiduSj sp. nov. 



A single tooth of Acrodus is an interesting addition to the 

 known fauna of the Bahia sandstones. It is elongated in 

 shape, measuring only 0*004 m. in length and 0'0015 m. 

 in maximum breadth ; the coronal surface is rounded and 

 slightly raised mesially in the usual manner ; and the apex 



