Q 
148 ON RHAMPHORHYNCHUS BUCKLANDI 
cavities enclosed by bone (the orbits and the nasal apertures), the 
Rhamphorhynchi have a third cavity interposed between the nares 
and the orbits; and they may possess a sclerotic ring. Their teeth, 
which are very long and curved, only the foremost and hindmost 
being short, do not reach the anterior end of the premaxilla and 
mandible, but they extend back to the orbits. The tail is very long, 
far surpassing in length the rest of the vertebral column, and con- 
sisting of more than 30 vertebre, which are at first short, but 
rapidly elongate, retain their length for a considerable distance, and 
then gradually diminish. The caudal vertebra, with the exception 
of the most anterior, which remain movable, are immovably united 
together by long bony fibres, externally invested by a firm sheath, so 
that the tail is always stiffly extended. Furthermore, according to. 
Wagner, the cervical vertebre of the Rhamphorhyuchi are as broad as 
they are long, the dentata forming the only exception to this rule. 
The coracoid and scapula may be anchylosed or otherwise. The 
fourth metacarpal bone is always far shorter than half the length of 
the fore-arm. 
The Rhamphorhynchi have already undergone a further sub- 
division by the separation, as a distinct genus, of the Liassic X. 
macronyx) of our own country. The specimen of that species origin- 
ally obtained and described by Dr. Buckland is, as is well known, 
devoid of the head; but Professor Von Meyer’s observations on 
German specimens, made and published so long ago as 1846, supplied 
this deficiency, so far as the lower jaw is concerned :— 
“Behind the sharp, upwardly-bent, edentulous point of the lower 
jaw, there are on each side, as far as the symphysis extends, three 
large teeth set at a certain distance from one another. To these 
succeed a series of close-set oval alveoli for smaller teeth, which are 
situated upon the separate rami of the mandibles, and are numerous.” ? 
Von Meyer’s discovery of the remarkable characters of the den- 
tition of Rhamphorhynchus macronyx has been confirmed by a 
specimen which has recently come to light in this country, and has 
been described by Professor Owen under the name of Dimorphodon. 
I am not aware that this description (which, as I am informed, was 
read before the British Association at its last meeting) has yet been 
published ;* but as the specimen forms a part of the collection of the 
1 Geol. Trans. 2 ser. vol. iii. p. 217, pl. 27. 
® Paleontographica, vol. i. p. 6. 
3 The abstract of Professor Owen’s Memoir, now published in the Report of the British 
Association for 1858, contains a full account of the dentition of Dzmorphodon, and must, of 
course, be considered to have priority over any statement on the subject in the text, which I 
