CRTPTOCLEIDUS OXONIENSIS. 189 



the tibia ; distally it carries the first distal carpal and has a short surface for the 

 preaxial part of the second. In some specimens (see text-fig. 91, B) there is a small 

 accessory ossicle {a.o.) articulating with the preaxial border of the tibiale near its 

 proximal end. The presence of this accessory ossicle may indicate that although the hind 

 paddle is little expanded in comparison with the fore paddle, there is nevertheless a 

 tendency towards such an enlargement. The intermedium (int.) has a short facet for 

 the tibia and a longer one for the fibula, with which also the fibulare (Jib.) articulates ; 

 the postaxial border of the last-mentioned bone is thin and convex. Of the three 

 distal carpals, the first articulates with the tibiale alone, the second with the tibiale and 

 intermedium, the third with the intermedium and fibulare, while its postaxial border 

 is in contact with the fifth metatarsal, which, as usual, articulates directly -with the 

 fibulare. All the metatarsals are flattened, and the same is the case in a decreasing 

 degree with the first two or three roAvs of phalanges. The more distal plialanges are 

 more cylindrical and constricted in the middle till near the ends of the digits, where 

 they become more flattened again ; the terminal pheilanges are mere nodules of bone. 

 The articular surfaces of the phalanges are somewhat convex and the articulations 

 between the successive phalanges of one digit usually alternate more or less regularly 

 with those of the adjacent digits. In one nearly complete hind paddle (E. 3703, 

 text-fig. 93) the numbers of the phalanges in the digits from the first to the fifth 

 are 3, 9, 13, 13, 12. 



A semi-diagrammatic restoration of the complete skeleton of Cryptodeidus oxoniensis 

 is given in text-fig. 94. This drawing is made almost entirely from the skeleton of the 

 adult (E. 2860) mounted in the Gallery of Fossil Reptiles, British Museum (see 

 Frontispiece), and used as a basis for the description of the skeleton given above. 

 'Ihe chief points of difference from Murcenosaurus shown in this diagram are the 

 relatively larger head, shorter neck, and more expanded fore paddles ; the important 

 difierences in the shoulder-girdle and pelvis cannot be shown in a side view. 



K. 2860 (Leeds Coll. 14). An almost complete skeleton of a nearly adult individual (Frontispiece). 

 The skull is broken and incomplete, the parts preserved being : — basioccipital (PI. IX. 

 figs. 1, la), exoccipital, opisthotic (PI. IX. figs. 1, 1 a), supraoccipltal (PI. IX. figs. 1, la), 

 basisphenoid (PI. IX. fig. 2), parietals, i'rontals, quadrate and squamosal (PI. IX. fig. 3), 

 premaxillse (part), portions of pterygoids. The mandible is nearly complete. The 

 vertebral column consists of the atlas and axis (text-fig. 78, C & D) and thirty other 

 cervicals, two or three pectorals, twenty-one or twenty-two dorsals, three or four sacrals 

 and twenty-two caudals, the distal portion of the tail being wanting ; most of the vertebrte 

 have their arches and ribs preserved : in the cervical and caudal regions the ribs in 

 most cases have not 3'et fused with the centra. There are (as mounted) six rows of ab- 

 dominal ribs, each consisting of a median element and three lateral pairs. The shoulder- 

 girdle is complete ; the fore paddles (text-fig. 91, A) want some of the phalanges ; the 

 pelvis is complete ; the hind paddles (text-fig. 91, B) want the proximal end of the right 

 femur, some tarsals, and phalanges. This specimen, which is mounted in the Gallery of 



