128 Descriptions of Neiv Fossil Fishes from the Trias. 



entire length ; all the bones of the head marked with strong raised lines, 

 those of the upper surface somewhat radiate ; on the opercula, maxilla- 

 ries, mandibles, and gular plates, more or less undulately parallel and 

 forked. The dorsal fin is of medium size, and placed near the centre of 

 the back ; the anal is set far back, reaching nearly to the caudal ; caudal 

 small, forked, the scales and vertebral column reaching distinctly into 

 the upper lobe. The scales on the anterior portion of the body are twice 

 or three times as long as high, and are marked with strong raised lines. 

 In the middle and posterior portions, the scales are very long and narrow, 

 five or six times as long as high, and traversed by a superficial furrow, 

 which generally reaches from the anterior end half or two-thirds the 

 length, and is again resumed on the posterior margiu ; by this the extremi- 

 ties of the scale are forked. On the anterior portion of the abdominal 

 surface the scales are exceedingly narrow, acute, and spine-like. Vertebral 

 column partially ossified. 



On comparing our fish with the figure and description of 

 Ft. Bollensis, Ag. (Poiss. Foss., Tom. 2, Tab. 85 b.), it will be 

 seen that it differs from that species in the position of the 

 dorsal fin, which is placed more anteriorly, in the details of 

 the scale and head-markings, and in the greater degree to 

 which the tail is vertebrated and the spinal column ossified. 

 From Pt minor, Egerton (Mem. Geol. Sur., Dec. VI, PI. VIII), 

 our species is easily distinguished by its much greater size, 

 narrower scales, and more vertebrated tail. From Pt. curtus, 

 Egerton (Mem. Geol. Sur., Dec. VIII, PI. VIII), it differs in 

 its more elongated form, in the plication of the scales, and the 

 more heterocercal tail. 



The discovery in our so-called Triassic rocks of a species 

 of Ptycholepis — a genus before found only in the Lias of 

 Europe — might seem to open up again the long-debated ques- 

 tion of the age of the " New Ked Sandstone" of the Atlantic 

 States ; but in fact it does not seriously invalidate the conclu- 

 sion, based on other evidence, that this series of strata? 

 though perhaps not strictly the equivalent of the Trias of 

 Europe, and it may be covering with its upper beds a portion 

 of the Jura, still is, on the whole, rather of Triassic than of 

 later date ; but the fish now described is a new species, and is 

 more heterocercal, i. e., has the vertebral column prolonged to 

 a greater distance into the upper lobe of the tail, than its 

 European Liassic representatives. Without attaching too 

 much importance to this character, we may fairly infer that it 

 indicates a little earlier date. 



Locality, Durham, Conn. 



