468 LOWER VERTEBRATES. 



The Pterodactyls had the jaws provided with teeth, planted some little distance 

 from each other, and long and slender, which were probably of use in securing fish and 

 smaller reptiles. The tail was sliort and insignificant, there being a regular decrease 

 in the size of the vertebrae from the neck posteriorly. The centra were, like those of 

 existing crocodiles, most lizards, and all ophidians, concave anteriorly and convex ])0S- 

 teriorly. Though good flyers, the pterodactyls were able to make but poor progress 

 on land, and probably crawled along, when obliged to, as do the bats of to-day. 

 When resting, they ])robably suspended themselves to the cliffs, or to the branches of 

 trees, the fingers seeming to indicate this habit. Pterodacttjlus axissirostris inhabited 

 the lowlands of Germany, and was about a foot in length. Many other species are 

 known from the European deposits. America can boast of but few species, but 

 such as we have are of the largest size. J', umbrosus, from the Kansas chalk, had an 

 alar extent of nearly twenty-five feet, while P. occidentalis measured eighteen. The 

 Pteranodons differed from the pterodactyls in having the jaws destitute of teeth. 

 They were, however, probably armed with horn. 



Rhamjyhorhynchus is a genus of flying reptiles which inhabited Europe during the 

 Jurassic period. The jaws were provided with long, sharp teeth, the eyes were large 

 and well developed, and the flying membrane was supported, as in the pterodactyl, by 

 the long ulnar fingers, and was of such a size as to easily support the body. The most 

 peculiar feature, however, was the elongated tail, which equalled one of the wings in 

 length. R. ]}hyllurus carried at the end of this appendage a terminal, fan-like rudder, 

 which was of use in directing the reptile's flight. Almost perfect remains have been 

 found in the lithographic slate of Germany. 



The European Dimoriyhodon had teeth of two kinds ; those of the anterior portion 

 of the jaw being large and long, while behin<l these was a series smaller and more com- 

 pressed. The skull of D. macroni/x was about eight inches long, and the wings ex- 

 panded four feet. It is the oldest known form of the order. 



The long series of cold-blooded vertebrates has been reviewed. Next come those 

 ■whose blood is considerably wanner than the medium in which they live. The transi- 

 tion, however, is not abrupt. We have seen that some of the rejitiles, especially the 

 extinct forms, have avian tendencies. Among the birds, on the other hand, we shall 

 see forms which have many reptilian features. In fact, the relationship existing be- 

 tween the reptiles and birds is closer than that between the reptiles and the forms 

 with which, by the exigencies of publication, they are associated in this volume. By 

 Huxley these two — Reptiles and Birds — are united in a grou]), Sauropsida. 



Hekmon C. Bumpus. 



