PTEROSAURIA. 273 



of the side. The neural arch is confluent with the centrum. 

 The anterior ribs have a bifurcate head. The dentition is 

 thecodont. 



A specimen of Pterodaetyle, from Bavarian lithographic 

 slate, shewing apparently but two phalanges in the wiDg- 

 finger, represents a family (Diarthri), and a genus Orni- 

 thopterus, in the system of V. Meyer.* The normal number of 

 phalanges in this characteristic digit of a Pterosaur is four. 

 The metacarpal bone varies in relative length in different 

 species. In Pter. longirostris it is more than two-thirds the 

 length of the first phalanx, in Pter. longicollum it is five- 

 sixths that length ; whilst in Pter. Gemmingi it is less than 

 one-fifth the length of the phalanx it supports. Other 

 variations are indicated by such specific names as, macronyx 

 long-clawed, micronyx small-clawed, crassipes thick-footed, 

 longipes long-footed, — longirostris, lyrevirostris, crassirostris, 

 conirostris, compressirostris, scolopaciceps, simus, relating to 

 various shapes of the head, — medius, grandis, vulturinus, 

 giganteus, relating to size of body, etc. The characters here 

 adopted for the genera of Pterosauria are taken from the 

 dental system. 



Genus Dimorphodon, Ow. 



Sp. Dimorphodon macronyx, Bkd. — In this species, from 

 the lower lias of Dorsetshire, the teeth are of two kinds ; a 

 few at the fore part of the jaws are long, large, sharp-pointed, 

 with a full elliptical base ; behind them is a close-set row of 

 short, compressed, very small lancet-shaped teeth. In a 

 specimen from Lyme Eegis, the skull is 8 inches long, and 

 the expanse of wing about 4 feet. There is no evidence of 

 this species having had a long tail. 



Genus Bamphorhynchus, Yon Meyer. — In this genus the 

 fore part of each jaw is without teeth, and may have been 

 encased by a horny beak, but behind the edentulous produc- 



* " Eeplilien aus dera Litliographischen Scbiefer,'* fol. 1859. p. 24. 



T 



