48 THE EXTINCT BATRACHIA, EEPTILIA 



The end of the muzzle was broken from a part or the whole of the cranium, which has not been rediscovered, 

 though Dr. Turner has made careful search. It was found in front of the vertebra? here regarded as cervical, at some 

 distance from them. 



The whole skeleton has been under considerable pressure, so that most of the ribs have been pressed flat on the 

 vertebra; the long parapophyses of the cervicals have most of them been fractured at their bases and compressed, 

 those of opposite sides thus approaching more nearly in the form of chevron bones than they otherwise would have 

 done. The proximal cervicals are obliquely flattened by the pressure; the other cervicals have the bodies naturally 

 flat, with the articular surfaces much less so than the median portion. Some of the caudals are obliquely distorted. 



Description — Vertebra. — The neck may be safely assumed as a point of departure, as it consists of above sixty 

 mostly continuous vertebra, which graduate to an atlas of very slender proportions. Most of them preserve more or 

 less developed parapophyses. At the posterior extremity of this series, sixteen are perfectly continuous, and in this 

 portion a great gradation in form is apparent. The anterior are narrow, compressed, and similar to the more distal 

 cervicals in the elevated position of the lateral angle; the anterior are subqnadrate, thick, and with lower lateral rib, 

 and stronger ? pleurapophysis. In these respects the latter resemble the dorsals which follow, towards what I believe 

 to be the tail. Four anterior dorsals are in one mass (figured in plate 3); in this series the lateral angle first approach- 

 ing, is finally lost in the margin of the rib-pit, the posterior thus resembling other dorsals. There can be so far little 

 doubt that the anterior and posterior extremities of the masses are correctly interpreted. 



In a series of four anterior dorsals, which like the preceding, are in their original continuous mass, those of one 

 extremity have centra rounded in section, with inferior rib-pits; those of the other have quadrate centra and elevated 

 diapophyses; the former have the character of the first dorsals, the latter of the median dorsals. The posterior dor- 

 sals and anterior caudals form in like manner a continuous series of eleven vertebra, fractured in four places. In 

 them the diapophyses steadily descend, reaching the inferior plane in the last, thus with the reduction of the venous 

 foramina to one, at the seventh, indicating the point of transition from dorsal to caudal series. The zygapophyses 

 preserve the usual arrangement, but are much compressed, so that the posterior or down-looking, are confluent, and 

 scarcely separated by an emargination. 



The neural spines at their bases have a slight posterior obliquity, and the superior portion leans strongly in the - 

 anterior direction. The inferior limbs of the cervical pleurapophyses appear to be entirely wanting. The articular 

 faces for the chevron bones are seen at the extremity of the inferior rib of the caudal. 



Of the cervicals there are both axis and atlas. Of the caudals, probably the distal half, at least, is lost. A single 

 vertebra near the middle does not relate to either of those anterior or posterior to it. There are, therefore, at least 

 four lost from that region also. 



There is a considerable interruption immediately anterior to the last dorsal vertebra. Three large vertebra, with 

 long diapophyses, belonging here, were imbedded in the hard matrix which protected the pelvic arch. These 

 are far from relating immediately to the vertebra preserved before and behind them. I estimate the number missing 

 as follows: Seven of the fourteen dorsals preserved have more or less elongate diapophyses. In the Plesiosauri, 

 vertebra of this character, are much more numerous ; in P. homalospondylus Owen gives seventeen. If we add 

 ten to the series in the present species it will give the abdominal space between the adjacent margins of the o. o. pubis 

 and coracoidea an extent equal to the length of the pelvic arch. This is relatively shorter than iu the Plesiosauri. 

 Dr. Turner found that a space of " three or four" feet intervened between the two portions of the skeleton, which was 

 otherwise continuous. I think ten an average number to represent safely the missing dorsals. 



From the cervical proximal regions probably three vertebra are missing from two interruptions. The remainder 

 of the cervical series exhibits three interruptions. Most of the proximals have been broken medially, leaving the 

 ticulations solid, an advantage in determining their continuity. Three vertebra and one-half are thus found to be 

 missing in this region. 



The whole number of vertebra preserved and lost, with the relative lengths of each, may be stated as follows: 



