On the Osteology of Nyctosaurus 163 



described and partly figured without certain errors into which he has 

 fallen, and that the peculiar "spiral" condyles of both Pteranodon and 

 Nyctodactylus have likewise been described and figured, without, however, 

 their having suggested to any one the probability that the animals dis- 

 located their jaws in deglutition. 



