Cope.] 45b [^Nov. 15, 



region. The palatopterygoid arch has the relations prevalent in the 

 Stegocephalia, but what is novel so far, its anterior and chiefly palatine 

 portion carries a single series of teeth on the external and anterior 

 border, which is concentric with the premaxillo-maxillary series, as in 

 Cryptobranchus. Posterior to this is a pair of straight series of teeth, 

 probably on the vomers, which form an anteriorly directed right-angle 

 at the middle line. They do not extend so far posteriorly as do the max- 

 illary teeth, and the latter do not extend so far posteriorly as the ptery- 

 gopalatines, which terminate at a straight linedrawn through the posterior 

 borders of the orbits. The posterior nostrils are situated between the 

 two series of palatal teeth. The external nostrils open forwards and 

 outwards. Maxillary and premaxillary teeth twenty-three on each side. 

 Palatines, twenty-four ; vomerines, ten. 



The composition of the huge horns is thus the result of the fusion of 

 the three posterolateral roof-elements into one, thus obliterating the 

 notch which separates the tabular from the quadratojugal bones in most 

 other Stegocephalia. 



DiPLOCATJLUS LIMBATUS, Sp. nOV. 



Tills species is represented by a number of fragmentarj'^ skeletons and 

 skulls. One of these I describe as the type since it displays more of the 

 characters than any other, but it is nevertheless damaged anterior to the 

 orbits, so that the form of the muzzle is not accurately determinable. 



The character of the species is seen in the horns. These are much less 

 produced relatively to other regions than in the D. magnicornis, and the 

 postquadrate (quadratojugal) element is more distinct, and terminates in 

 a separate apex below the principal horn. This tract, which is fused with 

 the principal bone in the D. mognicornis, is separated from it by a groove 

 in the D limbntus, and the large fossa which it encloses with the inferior 

 side of the principal horn looks inwards at an angle of 45°, while it looks 

 downwards in the D. magnicornis. The terminal angle of the quadratoju- 

 gal (postquadrate) body forms a prominent compressed offset, rather than 

 a free apex. In one specimen of large size it is infero-lateral ; in the 

 type, entirely inferior. The principal horn is shorter and narrower than 

 in the D. magnicornis, and less divaricate. 



As the mandibular rami are in place and their extremities are entire, 

 the length of the muzzle can be inferred. It is relatively longer and less 

 broadly rounded than in the D. magnicornis. The surfaces of the skull 

 are sculptured in honeycomb pattern, as in the type species. 



Measurements. mm. 



Length of skull on median line 93 



" " to extremity of horn 220 



Width of skull at posterior border 160 



" base of horn 51 



Length from angle of mandible to end of horn 115 



" " " postquadrate process 65 



