AMERICAN LABYRINTHODONTIDM 577 



The transverse is a small bone, about i4 cm long by 3 cm broad, 

 which articulates with the maxillary on the outside, with the pterygoid 

 on the inside, and with the palatine in front. The suture between 

 the transverse and the pterygoid has been definitely determined 

 only on the right side of A, but it is indicated on the left side of the 

 same skull and on the left side of B, where the bones are not so well 

 preserved. The suture between it and the maxilla is distinct, but 

 the one between it and the palatine is almost indistinguishable; only 

 on the right side of A can it be distinguished with any degree of 

 certainty, and even here a second line back of the one indicated in 

 Plate II has very much the indication of a suture. On the right side 

 of the same skull the bones are partially lost in the place where the 

 palatine and transverse meet, but there is an indication of a suture 

 in the same region as the one shown on the left side. 



Viewed from the under side of the skull, the premaxillae are nearly 

 rectangular in shape. Each is pierced by a large opening for the 

 passage of a mandibular tooth. This opening occupies more than 

 half of the area of the bone. It is conical in shape, with the apex 

 of the cone passing through the anterior end of the external nares. 

 The suture between the premaxillae and the maxillae has not been 

 definitely determined, but it appears to be just outside the opening 

 for the mandibular tooth. The teeth are all broken off at the surface 

 of the bone. Their sockets are no larger than those on the anterior 

 part of the maxillae. The suture between the premaxillae and nasals 

 is directly between the external nares. 



The maxillae are very slender. They extend from just outside 

 the external nares to the anterior end of the infratemporal foramen. 

 They bear a single series of small teeth that seem to increase gradually 

 in size anteriorly. Only the roots of the teeth are preserved, and 

 unfortunately most of them are badly obscured. 



The palatine foramina are long, narrow posteriorly and expanded 

 anteriorly. The infratemporal foramina are short and broad. The 

 internal nares are large, oval, and situated near the anterior end of 

 the palatine foramina. The premaxillary foramina are large and 

 nearly circular. 



The openings on the inferior side of the skull are almost perfectly 

 shown in both specimens. The following table gives their dimensions : 



