224 



THE EXTINCT BATRACHIA, KEPTILTA 



mi any of the teeth. The apex curves gently inwards. From the above, the greater compression of the posterior teeth 

 may be inferred. 



The pterygoid teeth present no cutting angles, and are gently curved backwards. Like the maxillaries, the an- 

 terior mandibular teeth have no posterior edged angle, but they have one on the posterior part of the outer side, di- 

 viding the clown into two very unequal faces, the inner being much the larger. This ridge becomes more posterior 

 in the hinder teeth, but the outer facet is never larger than the inner. The crown is faintly ribbed, but not so as to 

 be facetted, as in Holcodus and Mosasaurus. Number of teeth on each side: prcmax., 2; max., eleven functional, and 

 alveola; in intervals for six more; mandibulars, fifteen, with alveola for three others. 



The usual vasculo-neural foramina occur along the faces of the maxillary and dentary bones. The series of the 

 lirst commences by two small ones, out! above the Other, ni'iir its extremity; this is followed by a, close series, there 

 being three opposite two adjacent alveoli. They arc soon more widely spaced, and number sixteen altogether. There 

 are eleven on the dentary bone, quite widely spaced behind; the anterior small. 



The cranial bones are all minutely striate, the upper surfaces of the parietal and occipital most strongly. The cor- 

 onoid process is very rugose on the inner aspect; as are the posterior margins of the angular, up to the terminal line, 

 where would appear to have been a band of cartilage; similar to that at the articulation of the ribs, or like the ends of 

 the caudal neural spines. The sutural margin* of the angular is marked by delicate radii. The external surfaces of 

 the mandibular bones are minutely striate, like the bones of many fishes. 



The proximal part of the internal lamina of the splenial is concave. It does not extend to the end of the ramus, 

 so that tin; meckellian groove is open for one-fourth the length of the latter. The outer face of the ramus is regularly 

 convex. The splenial disappears from view at a point opposite the fourth tooth from behind. The inferior ridge of 

 the mandible is straight, to near the splenial articulation, where it is directed slightly outwards. On the proximal 



part of the mandible, if is gently convex Inwards to nearly opposite; tin; anterior part of the quadrate ootylus, where 



it, is convex outwards; the plane of the angle; is then directed slightly inwards, and is very rugose below. 



VV r hen in position, the piano of the proximal part of the ramus is more horizontal than that of the distal. From the 

 splenial joint the inferior margin becomes more horizontal, until the broad angle; is nearly transverse, anil with a, slight 

 inward curve. What appears when examined separately to be the external face, becomes largely inferior, making an 

 angle of 45° with the horizontal. 



The fossa; are strongly marked. The outer edge of the coronoid rolls back, and the upper edge of the articular 

 forms a ridges enclosing the internal fossa. The quadrate cotylus is sub-longitudinal, inclining inwards and forwards, 

 and with a high anterior margin. 



Measurements. 

 Length from end muzzle to occip. condyle, 



" " " " parietal fontanelle, 



" " " " poster, extrem. nares, 



" " " " end maxillary, 



" " " " " malar process do., 



" " " " prc-frontal angle', 



" " " " post-frontal " 



" (median) temporal fossa (antcro-posterior), 

 Width at anterior extrem. maxillaries, 



" " pre-frontals, 



" " post-freintals, 



" between poster, extrem. squamosals, 



" " anter. extrem. proeitics, 



" " parietal crests behind, 



" " " " at parietal fontanelle, 



" of suspi'iisorium, 



" " septum narium at poster, extrem., 

 Length snspensorium (without squamosal), 



In, 



Lin. 



14 



4 



11 



■\ 



(i 



(! 





11 







(i 



8 



11 



11 



0.5 



1 



!) 





1) 



4 



1 



5 





5 



1.9 





Ki.:s 





5.5 





148 





IS. 7 





7.2 





10 



