686 



PROF. OWEN ON THE RANK AND AFFINITIES IN 



mosal, 27, for the suspension of the tympanic, 28 ; the pair of hypa- 

 pophyses, i', from the basioccipital, i ; the greater proportion of the 

 occipital surface contributed by the median part of the coalesced 



Fig. 2. 



Amblyrhynchus. 

 Occipital region of skull. 



parietals, 7, and by the lateral extensions, 7', which are relatively 

 greater ; the mastoid, 8, moreover, is pushed inwards by the junc- 

 tion of 7' with 27 ; finally, the large vacuities between 7' and 2-4 *. 



An extreme modification of the occipital is shown in the Ophidian 

 reptiles. In Python reticulatus the basioccipital forms the lower 

 part of the condyle, fig. 3, 1, supported on a short peduncle, on each 



Fig. 3. 



Fig. 4. 



Pytkon. 

 Back and side views of occipital region of skull. 



side of the base of which is a low transverse ridge for attachment of 

 the capsular ligament. The siugle hypapophysis is shown at i'„ 

 The exoccipitals (2) contribute the upper and lateral portions of the 

 condyle, and unite together above the occipital foramen. Each ex- 

 occipital has a small process supplementing that from the basioccipital 

 for the attachment of the strong capsular ligament of the occipito- 



* These characters are well shown in the corresponding view of the same 

 species in Steindachner's Monograph, pi. v. fig. 8 ; but the constituent bones are 

 not indicated, and the suture between the mastoid and parietal is omitted on the 

 right side, and feebly marked on the left. 



