Cope.l j <* [April 17, 



Enchodus subcequilateralis, sp. nov. ; Oaleocerdo pristodontus Agass. ; 

 Apocopodon sericeus, sp. nov. 



? . Province of Sergipe del Rey. Pycnodus flabellatus, sp. nov. 



Jukassic. Province of Ceara. Ancedopogon tenuidens Cope. Aspido- 

 rhynchus, sp. 



Carboniferous. Province of San Paolo. Stereosternum tumidum, 

 sp. nov. 



The following pages contain the detailed descriptions of the new species, 

 and the determination of their affinities. Others yet remain to he deter- 

 mined. 



PISCES. 



Apocopodon sericeus, gen. et sp. nov. Myliohatidorum. 



Char. gen. Founded on teeth which formed a pavement like that of 

 Myliobatis, but which are mostly separated in the specimen. These con- 

 sist of longer ones of a median series, and smaller ones of the lateral series. 

 The teeth of the median series are shorter than in the typical forms referred 

 to Myliobatis, having rather the proportions characteristic of Zygobatis. 

 They differ from the corresponding teeth in both genera in being exactly 

 parallelogrammic in outline ; that is, the extremities are truncated instead 

 of angulated as in those genera.* The lateral teeth display the usual an- 

 gulation among themselves, though doubtless joined by a straight suture 

 to the middle row. The roots are well distinguished from the crowns, and 

 are short. Their grooves are very shallow, or merely indicated. The 

 triturating surface is covered by a dense layer which is wrinkled like the 

 sides of the crown, and is continuous with it. 



Char, specif. The teeth are robust and indicate a species of considerable 

 size. The crowns are considerably more elevated than the roots, and have 

 perpendicular sides. The sutural surfaces are straight, and marked by fine 

 grooving which runs at right angles to the grinding face, and is continu- 

 ous with the wrinkling of the latter on the long sides of the crown. From 

 this it follows that the wrinkling crosses the grinding face at right angles 

 to its long diameter. There are in the wrinkling six ridges to a millimeter. 

 The roots are constricted from the crowns by a groove, which is itself 

 divided by a narrow collar-like rib, resembling cement, which is ex- 

 pressed on the junction of two pieces by pressure, grown cold. The 

 sizes of the teeth diminish externally. The roots of those of the antepe- 

 nultimate are crossed by four shallow grooves, and those of the penulti- 

 mate by two. External row lost. Six grooves cross the root of one of the 

 larger teeth. 



Measurements. M. 



(transverse 024 

 anteroposterior 013 

 vertical 021 



Vertical diameter of root of do 006 



•Que end of one of the large teeth has the usual two face?. 



