212 PROCEEDINGS OF THE ACADEMY OF 



on each side, not attaining the probable position of the nostrils. Each is di- 

 vided by a longitndiual groove, which is probably a suture, and which would 

 then divide the frontals from the parietals. The frontals would then divide 

 the parietals entirely, as they do in Menopoma for the anterior half of their 

 length. This would give the frontals a narrow form, acuminate in front, and 

 bounded behind by a regular coarse, zig-zag transverse suture. The cranium 

 behind this point is rugose, and the surface not well preserved, and it can only 

 be said that two irregular grooves converge to a point between the posterior 

 extremities of the frontals, like the boundaries of the supraoccipital. The 

 posterior boundary of the cranium with the condyles cannot be readily deter- 

 mined. When the postorbital roof bone is raised up, the meeting of two gular 

 dermal bones, as I interpret them, is seen. One of these is a plate directed 

 backwards and outwards, bearing minute radiating lines on its upper surface. 

 It meets a similar flat plate directed forwards and outwards, with similar lines 

 radiating to the circumference. The inner margins of these plates were not 

 seen. 



The orbits are remarkably small, and situated probably near the middle of 

 the longitudinal measurement of the cranium. The external nares are not 

 defined, but symmetrical depressions in the position they usually occupy in 

 Salamanders are distinct. 



The general form recalls Menopoma, particularly the necessarily small eyes. 

 A slender curved bone with a slightly dilated and truncate extremity, lying by 

 the cranium in connection with the mandible, is like a branchihyal of that 

 genus. Nevertheless it cannot be positively assigned to this genus, as numer- 

 ous scales of cycloid fishes are on the same block. 



Pariostegus myops Cope. 



The surfaces of the cranial bones are little sculptured ; there are small tu- 

 berculiform elevations on the parietals and more numerous ones on the pre- 

 orbitals. Thepostorbitals show the strongest markings of elongate pits which 

 radiate to their circumference, leaving a smooth obtuse border. The nasals 

 present a series of small warts at a little distance on each side of their com- 

 mon suture, and transverse to it. The surface of the maxillary is marked with 

 longitudional grooves and shallow pits. 



No suture separating maxillaries and premaxillaries can be traced with cer- 

 tainty, though the bones of the jaw are interrupted at the usual place of suture, 

 opposite the nostril. 



3Ieasurements. 



Lin. 



Length of specimen (including mandible) 18 



Width between outer convexities postorbitals 17 



" " inner borders orbits 11 



" of same without preorbitals 8 



" of nasals at middle 2-5 



" orbit 1-5 



Length of frontal nasal premaxillary 11. 



" " supposed branchihyal 12. 



The name is derived from the roof-like postorbitals with free lateral margin. 

 Locality. — Coal bed of the Keuper Triassic, Chatham Co., North Carolina. 

 The species was discovered by Prof. Jos. Leidy, who 4ianded it to me for de- 

 scription. It is in the Museum of the Academy of Nat. Sciences of this city. 



DENDRERPETON Owen. 



Journal Geol. Soc. London, 1853, p. 81. 



In the form of the cranium this genus differs from Brachydectes and Ophi- 

 derpeton, much as Menopoma does from Amphiuma. Two species appear to 

 have left their remains in the coal measures at Linton, Ohio. 



[Sept. 



