LIASSIC PTERODACTYLES. 493 



exceeded the sacral formula prevailing in existing Crocodilia and Lacertilia, we should 

 gain no firm ground therefrom for predicating Avian aifinity or for building thereon a 

 derivative hypothesis of the class of Birds. Many existing Chelonian Reptiles have a 

 sacrum composed of more than two vertebrae. ^ 



The perfect specimen of tail-vertebrae and associated bone-tendons in the specimen of 

 Bhaviphorhpichus Meyeri completes satisfactorily the restoration of this part of the vertebral 

 column in B'morphodon. Before the discovery of Rhampliorhptchus, the order Pterosauria 

 was known only through species having the tail very short. Not only were the vertebrES 

 comparatively few, estimated at twelve or thirteen in Ftcrodactylus lonyirosfris,^ at 

 fourteen in Pt. spectabilis, at fifteen in Pt. scolopaciceps,^ and as low as ten in Pt. 

 Meyeri* but they were very small and short. The great advocate of the Avian affinity 

 of the Pterosaurs, Soemmerring, based his chief argument in this character. But 

 CuviER was able to adduce instances of Beptilia with tails as short ; and he might now 

 have cited a Bird with a tail-skeleton as long, as slender, and as many-jointed as in divers 

 Saurians.'^ The earliest indication of a range of variety in this part of the bony frame- 

 work of a Pterosaur was deduced, with his usual sagacity, by Buckland. 



In the original specimen of DimorpJiodon are three caudal vertebrae at the base of the 

 tail, marked K, in pi. xxvii of his Memoir, from the size of which vertebrae, togetlier with 

 the larger and longer legs, as compared with Pferodacfylus lonyirostris, Buckland 

 inferred tliat the entire " tail was probably longer, and may have co-operated with the 

 legs in expanding the membrane for flight." " " A long and powerful tail," he proceeds 

 to remark, " is in strict conformity with the character of a Lizard " (ib.).' 



Buckland would have had further direct confirmation of the length and strength of the 

 tail of his Lias Pterosaur, if he had recognised the series preserved at a, a, in his pi. xxvii, 

 as caudal vertebrae ; but they were conceived to belong to the neck, notwithstanding 

 their slenderness and length, and that around them were " small cylindrical bony 

 tendons, resembling the soft tendons that run parallel to the vertebrae in the tails of 

 Rats." ^ When the evidences of caudal structure were first recognised by Von Meyer, in 

 BhampJiorhynchus Gemmingi, he detected the homologous structures in pi. xxvii of 



^ ' Anat. of Vertebrates,' vol, i, p. 65. 



2 By Cuvier, vol. cit., p. 368. 



' Von Meyer, op. cit., p. 17. 



*Ib., p. 17. 



6 Owen "On the ArchcBopteryx" ' Philos. Trans.,' 1S63, p. 33, pis. i— iv. 



* Buckland, loc. cit., p. 221. 



"1 Archaopteryx had not then been discovered ; else, it might have been objected to the above hint of 

 affinity, not only that there had been short-tailed Pterodactyles, but also long-tailed Birds. 



8 "Mr. Clift and Mr. Broderip have discovered that the remaining cervical vertebrae are surrounded 

 with small cylindrical bony tendons of the size of a thread. These run parallel to the vertebrsE, like the 

 tendons that surround the tails of rats, and resemble the bony tendons that run along the back of the pigmy 

 musk and of many birds" (loc. cit., p. 218). 



