64 MAEINE EEPTILES OF THE OXFOED CLAY. 



R. 2180 (Leeds Coll. 76). The greater part o£ the skull and skeleton. The bones of the skull are 

 for the most part separated from each other and several are figured in the test, as 

 noted below. The portions preserved include : basioccipital, exoccipitals, basisphenoid 

 with parasphenoid attached (text-fig. 7), opisthotics, stapes, quadrates, quadrato-jugals 

 (text-fig. 10), jugals (text-fig. ]0), maxillae (text-fig. 13), premaxillse, nasals (text-fig. 12), 

 lachrymals (text-fig. 11), postorbitals (text-fig. 8), part of prefrontal, postfrontals, 

 together with fragments of squamosals and parietals and other roofing-bones of the 

 skull. The pterj-goids (text-fig. 17), one palatine, and perhaps the vomers are preserved. 

 The mandible (text-figs. 20 & 22) is nearly complete, only its tip being missing, and 

 the bones of the right ramus are mostly separate from each other. In this skull and 

 mandible many of the bones are crushed and some wanting, but the circumstance that 

 they are for the most part disarticulated makes the specimen especially valuable, and it 

 has been employed in the text in the description of many of the individual elements and 

 as the basis for the restoration given in text-fig. 23. A number of sclerotic plates, 

 mostly separated from each other and incomplete at their outer ends, are preserved 

 with this skull. There are also about half a dozen teeth, with slightly fluted, pointed 

 crowns and rather deeply grooved roots. The rest of the skeleton is represented by 

 the atlas, axis, thirty-two other precaudal vertebra, and twenty-four caudals : many of 

 these vertebral centra are much crushed and distorted and none remain united to 

 the neural arches. About thirty more or less imperfect and crushed neural arches 

 are preserved : of these about six, probably belonging to the anterior cervical s, seem 

 to be composed of two halves (neurapophyses), which united in suture with each other 

 in front and overlapped the anterior part of the next neural spine behind (text-fig. 29). 

 There are numerous double-headed precaudal ribs and a few single-headed caudal ribs, 

 mostly more or less imperfect. 



The shoulder-girdle is complete, though somewhat crushed. Both humeri are 

 preserved, also the radius, ulna, pisiform, radiale, intermedium, ulnare, and about thirty 

 other paddle-bones. 



The pelvis and hind limbs are wanting. — 



Some approximate measurements (in centimetres) of some parts of this skeleton are 

 given below :— 



Basioccipital : greatest width 7*9 



greatest length 6'5 



length of neural surface 4-0 



width of occipital condyle 5-9 



height of occipital condyle 4-6 



Basisphenoid and parasphenoid (text-fig. 7) : total length . . 30'0 



Parasphenoid : length of free portion . 23'5 



width at base . , 2-0 



Jugal (text-fig. 10) : total length . 26-5 



width of suborbital bar . . ... 2-0 



Lachrymal (text- fig. 11) : length of base 12"5 



height 6-4 



