On the Osteology of Nyctosaurus. 159 



much longer than forearm; phalanges proportionally long. No fibula 

 present; two tarsals only; fifth digit without phalanges. 



Ornithocheirina. Upper end of scapula thickened, articulating 

 with a supraneural plate. Head with a prominent parieto-occipital crest. 



Ornithocheirus. Jaws with teeth. 



Pteranodon (Omithostomd). Jaws wholly edentulous. 



NyctosaurincB. Scapula flattened spatulate above, not articulating 

 with supraneural plate. Humeral crest constricted; humerus propor- 

 tionally short, the digit long; no sagittal crest. 



Nyctosaurus, Ornithodesmus (?). 



In contradistinction to these characters I would define the Ptero- 

 dactylida as follows: I have never seen any specimen of this genus, and 

 must, therefore, rely entirely upon the descriptions and figures. The 

 characters hence are in a measure provisional. 



Pterodactylida. A distinct antorbital foramen present, sometimes 

 partly confluent with the nares; occiput not produced, jaws always with 

 teeth. No consolidation of the thoracic vertebrae or anchylosis of the 

 sternal ribs, the posterior ribs less slender. More than ten vertebras in 

 the dorsal region and less than six in the sacrum. Prepubes never co-ossi- 

 fied in the middle, and without anterior prolongation. Scapula longer 

 than the coracoid, more or less narrowed distally. Humerus and legs 

 relatively large, the forearm and wing finger relatively small; all the meta- 

 carpals articulating with the carpus. A fibula present. 



I am sure that all these characters are generalized ones, even as the 

 genus is older than those placed in the first group. It seems to me 

 especially that the shortening of the back, the consolidation of the early 

 dorsal vertebrae, and the elongation of the sacrum, with the greater elonga- 

 tion of the wing digit, are better evidences of relationships than is the 

 presence of the peculiar scapular articulation. 



Certain conclusions as to the habits of the Ornithocheiridd, as I here 

 define the family, seem inevitable from a better knowledge of their struc- 

 ture. Some of these conclusions I have already presented in a former 

 paper, and a further study only strengthens my belief in their justness. 



The neck was strong, with limited torsion, but with great power and 

 effectiveness in the antero-posterior flexion, thus rendering the beak very 

 effective in striking.* The marked posterior projection of the hind 

 zygaphophyses of the last cervical vertebra, quite unlike those of any 

 other vertebrae in the column, indicates, not that the neck turned back- 



* Plieninger (op. cit.) misquotes me in saying that " Williston glaubt, dass diese Art der 

 Articulation die Bewegung des Halses in verticaler Kichtung von vorne nach binten eingeschrankt 

 hat." What I said was: " Such a mode of articulation would seem to limit the motion to one in a 

 vertical, antero-posterior plane, while greatly strengthening the joints."— Kans. Univ. Quart., vi, p. 39. 



