SKULL REPTILES 



159 



arches, except in so far as the upper is represented by the elongate 

 squamosal and its ligamentary attachment to the parietal bone; 



Fig. 169. — Section of skull of Python (Butschli, '10). bo, basioccipital; bs, basi- 

 sphenoid; eo, exoccipital; /, frontal; m, maxilla; n, nasal; p, parietal; pi, palatine; pm, 

 premaxilla; po, prootic; pt, pterygoid; sm, septomaxillary; so, supraoccipital ; sq, squa- 

 mosal; V, vomer. 



its lower end is loosely connected with the upper end of the quadrate. 

 The postfrontal bone is usually well developed; Typhlops has lost 

 the squamosal. 



Pterygoids and frequently the pala- 

 tines bear acrodont teeth and are loosely 

 connected with the cranium, and those 

 of the two sides are remote from each 

 other. The pterygoids are long and 

 slender, articulating behind with basi- 

 sphenoid and quadrate, and connected 

 laterally with the maxilla by the trans- 

 versum. An epipterygoid is lacking and 

 the palatines do not articulate with 

 cranium or vomer. The exoccipitals, 

 which have a weak parotic process, 

 exclude the supraoccipital from the 

 foramen magnum; basisphenoid and 

 basioccipital are not fused, and the 

 former is either broad in front (some 

 poisonous species) or is continued for- 

 wards by a slender rostrum. 



The quadrate, articulated dorsally 

 with the squamosal and never with the 



parotic process, is very mobile and aids in the protrusion and 

 retraction of the lower jaw; its part in the erection of the fang 

 was mentioned above. The bones of the lower jaw are more exten- 



FiG. 170. — Diagram of skull of 

 Solenoglyph snake with open and 

 closed jaws (Biitschli, '10). m, 

 maxilla; md, mandible; p, poison 

 tooth; pf, prefrontal; pt, pterygoid; 

 q, quadrate; s, squamosal; t, 

 transversum. 



