526 S. IV. WILLI STON 



directed inwardly and anteriorly, closely approaching or touch- 

 ing its mate in the plane of the palate ; and a larger one, which 

 goes forward to beyond the middle of the narial vacuity, articu- 

 lating with the ectopterygoid, and distally, by a long suture, 

 with the palatine. Between the two there is an arrow-shaped 

 vacuity posteriorly, bounded behind by the basi-sphenoid, the 

 indentation for the head of the arrow formed by a small, thin 

 inner process. This form of the pterygoid, it will be seen, is 

 quite different from that figured and described by Woodward in 

 Rhamphorhynchus. The slender inner process does not turn 

 upward to meet a vomer, as Woodward thinks may be the case 

 in the skull described by him, and the processes which, in his 

 specimen, turn inward and upward are, in Nyctodactylns, closely 

 applied to the inner side of the palatines. The pterygoid does 

 not unite with the vomer in Nyctodactylus. 



The ectopterygoids are thin, narrow bones, articulating broadly 

 with the outer margin of the pterygoid, and exteriorly with the 

 inner side of the slender posterior extremity of the maxilla. The 

 bone is directed forward and outward, its concave margins form- 

 ing the anterior and posterior borders of the pterygo-jugal and 

 posterior palatine vacuities. 



The palatines are long, narrow, thin bones, articulating by a 

 long suture on the inner side with the pterygoid, and on the outer 

 side with the maxilla. Anteriorly the union with the maxilla or 

 vomers is indeterminable. 



The relations of the maxilla can be made out only in its pos- 

 terior part. Its union with the jugal has already been indicated. 

 Posteriorly it sends up a thin, curved process to meet the nasal, 

 forming the posterior inferior boundary of the nares. Back of 

 the thickened portion of this process there is a thin plate reach- 

 ing back under the superior process of the jugal, the bottom of 

 an oval depression or excavation, which clearly corresponds to 

 the antorbital vacuity of the earlier pterodactyls. From this it 

 is evident that the antorbital vacuity is not united with the nares 

 in either this genus or Ornitlwstoma. 



The vomer cannot be made out. If it forms a part of the 



