ON THE SKULL OF NYCTODACTYLUS, AN UPPER 

 CRETACEOUS PTERODACTYL. 



Elsewhere I have published a brief description, with a 

 restoration, 1 of an unusually complete specimen of Nyctodactylus, 

 recently collected by my assistant, Mr. H. T. Martin, in western 

 Kansas. At the time this restoration was made, the skull was 

 lying in its original matrix, with its palatal surface uppermost. 

 On account of its extreme delicacy, it was thought best then not 

 to attempt its removal. This, however, has since been done in 

 a most skillful manner by Mr. Martin, and it is now almost com- 

 pletely removed from the chalk in which it was embedded. Its 

 delicacy and fragility may be suspected from its weight, scarcely 

 thirty grammes, the mandible weighing about nine grammes 

 more. The remarkable perfection and relative freedom from 

 distortion render the specimen especially valuable for study. 

 The mandible was displaced, in no wise obscuring other parts. 

 The skull is of course depressed, but not so much as one might 

 expect from the position in which it was lying, and there is a 

 slight lateral compression to the right, but not enough to render 

 the interpretation of the characters at all difficult. I give here- 

 with a photographic reproduction of the back part of the skull, as 

 it was seen before removal from the matrix. The anterior por- 

 tion, on a separate block of matrix, has been omitted in order to 

 show the hyoid bones lying partly beneath it. In the drawings 

 I have attempted to restore the skull as nearly as possible to its 

 living condition. There is yet a possibility that I have made 

 the skull a little too broad, but, if so, the exaggeration must be so 

 small as to be scarcely appreciable. The drawings were made by 

 myself, at least insuring a careful study of the parts. 



The premaxillary doubtless comprises the whole anterior por- 

 tion of the beak, as in other known pterodactyls. In the middle 

 behind, it separates the nares by a rather broad, gently convex 



1 American Journal of Anatomy, Vol. I, p. 297. 



520 



