D.'C. -2, IfTO.] 039 [Cope. 



As will be secii, tlie fossils described ai-e evidently from a fresh water 

 basin, once a lake, wliicb has, at a comparatively late period of geological 

 time, been elevated and desiccated. 



The species and genera are chiefly cyprinidas, and from the number 

 of the former, ten, imx^ortant as throwing light on the character of the 

 forms of that family at a time not long preceding the establishment in 

 their present habitations of those now living. Remarks on these relations 

 are deferred to the close of the descriptions. 



CYPRINID^. 



Characters of the genera represented : — ■ 



A. Pharyngeal tooth series transverse to longer axis of the pharyngeal 

 bones. 



Pharyngeal teeth 0.4 — ?.? with compressed roots, and probably molar 

 or masticatory crowns on an oblique basis, the highest extremity being 

 inferior, the lowest superior. Diastichtjs. 



B. The pharyngeal tooth series very oblique to the longer axis of the 

 pharyngeal bone. 



Pharyngeal teeth 2.3(?4) — ??, with round bases, and probably conic 

 prehensile crowns ; no ala of the slender pharyngeal bones. 



Oligobelus. 

 G. The pharyngeal tooth series nearly in the longer axis of the pharyn- 

 geal bones. 



Pharyngeal teeth 3.5 — 4.3 conic prehensile. Semotilus. 



Pharyngeal teeth 0. 5 — ?.?, with short, compressed crowns and narrow, 

 transverse masticatory face, and no prehensile hook ; bone alate. 



Anchybopsis. 

 Pharyngeal teeth 0.4 — 4.0, or the outer row 1 or 3 rudimental ; crowns 

 molar, broad, truncate, with enamelled grinding surface. 



Mtlocyprinus, 



DIASTICIIUS. Cope. 



Genus novum. 



DiASTicirus MACEODON. Cope sp. nov. 



Represented by three right pharyngeal bones, of which the distal 

 extremities are lost. The proximal limb of the bone is long and flat, the 

 extremity first dilated, then contracted coincidently with a transverse 

 depression of the superior face, the end everted or expanded, with sym- 

 physeal surface within. There is no proper horizontal alar expanse, but 

 rather an anterior one, the front face (inferior when on a plane surface), 

 b-eing a little oblique. Tooth series in the line of the axis of the superior 

 limb of the pharyngeal bone, its base rising exteriorly and pi-oximally. 

 Outer face neaiiy vertical, grooved. The teeth are knocked off in all the 

 specimens ; their bases are a broad, oval or i^arallelogram. The form of 

 the crown is uncertain, but I suspect it to have been more or less truncate. 



