254 



EEPTILIA 



Dermodadylus, Marsh. Imperfectly known, perhaps belonging among the 

 Pterodermata. Upper Jura (Como Beds) ; Wyoming. 



f^^.^'^ 



Fig. 359. 



Pterodactylus elegans, Wagner. Lithographic Stone ; 

 Eichstiidt, Bavaria. Vi- 



Fig. 360. 



Pterodactylus spectaWlis, v. Meyer. Lithogi'apliic 

 Stone ; Bichstfidt, Bavaria. 3/^ (after H. v. Meyer). 



Family 2. Ornithocheiridae. Seeley. 



External nares confluent with antorhital vacuity. Teeth, when present, restricted 

 to posterior portion of the jatvs. Pectoral arch strong, coracoids and scapulae firmly 

 fused ; the former articulating with the sternum, and the latter by a large oblique 

 facette with a supraneural plate above the coossified anterior dorsal vertebrae. Proxi- 

 mal tarsals fused with the tibia; no fibula. Cretaceous. 



This family includes the largest known Pterosaurs, their wing expanse 

 varying between 1"5 and 5'8 m. In these highly specialised forms the anterior 

 extremities attained their greatest power, while the posterior pair were 

 weakened, and probably of slight use as locomotive organs. 



Pteranodon, Marsh (1 Ornithostoma, Seeley). Skull considerably elongated, 

 with slender, pointed, edentulous jaws, and a long thin supraoccipital crest. 

 Sclei'Otic ring present. Sternum keelless, but with a stout anterior median 

 projection. Sacral vertebrae seven in number. Anterior ribs stout, 

 coossified with their centra. Carpus composed of three bones in two rows. 

 Pubes band-like, coossified in the middle. Hind limbs relatively small ; 

 femur short and curved, with a small trochanter ; tarsus consisting of two 

 free bones in a single row. Fifth digit represented by a small claw-like 

 metatarsal ; median phalanges of second, third, and fourth digits very short ; 

 first and second digits without claws. Niobrara Cretaceous ; Kansas. 



