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Genus Menobranchus. 



582. The cranium of the Menobranchus (Menobranchus lateralis). 



In this skull the basioccipital is represented by the narrow posterior border of the common 

 basicranial plate, which bounds the foramen magnum below and separates the occipital con- 

 dyles. These are transversely oblong, convex vertically, concave transversely, developed from 

 the exoccipitals, which are separated above by a membranous or thin cartilaginous plate, repre- 

 senting the superoccipital : each exoccipital forms the posterior half of the otocrane, is per- 

 forated by the nervus vagus, and articulates above with the parietal and mastoid. The basi- 

 sphenoid is very broad and flat : the alisphenoids bound the fore part of the otocrane, trans- 

 mit the trigeminal nerve, and abut against the tympanic pedicle in its course backwards to 

 the mastoid. The parietals are divided by the sagittal suture and develope a small ridge there 

 posteriorly : each parietal sends down a process in front of the alisphenoid, which rests upon 

 the pterygoid, representing the so-called columella in Lizards. There are no maxillary bones. 

 The alveolar border of the premaxillaries, which supports a single row of long and slender 

 teeth, ten in number in each bone, terminates in a point projecting freely outwards and back- 

 wards. The vomero-palatine bones unite together anteriorly, but diverge posteriorly, where 

 they give attachment by their outer margin to the ptery golds. There is a single row of long 

 and sharp denticles upon the alveolar border of the vomero-palatines, and. behind this there 

 is a series of six or seven denticles on the outer and anterior border of each pterygoid. The 

 anterior teeth of the lower jaw pass into the interspace between the premaxillary and vomerine 

 teeth. The pterygoid teeth are opposed by a row of five or six teeth, forming a group be- 

 hind and distinct from those on the anterior half of the dentary bones. 



Presented by Prof. Owen, F.R.S. 



Genus Menopoma. 



583. The skeleton of the Menopome or Salamander of the Alleghany Mountains 



(Menopoma Alleghaniense). The number of vertebrae is 35. 



The first vertebra is without ribs ; the eighteen succeeding vertebrae have short, free, or 

 false vertebral ribs, ' pleurapophyses,' articulated to the extremities of transverse processes, 

 formed by ' parapophyses ' and ' diapophyses ' which intercept, prior to their confluence, an 

 arterial canal. These processes are enlarged in the twentieth vertebra, and a second rib-like 

 piece is articulated to the short and thick rudimental rib, the inferior or haemal arch being 

 completed by semi-ossified cartilage. The bones of the hinder extremity are articulated to the 

 junction of the second rib-like piece with the cartilage. The vertebra, completed by this 

 inferior arch, represents a sacral vertebra ; the second division of its rib answers to the ilium ; 

 the cartilage completing the arch, to the ' ischiutn ' or ' pubis.' Transverse processes, pro- 

 gressively decreasing in length, are developed from the six succeeding vertebrae. Osseous 

 rudiments of ribs are attached to the first of these, and cartilaginous rudiments to the three 

 following. Haemal arches are anchylosed to the under part of the centrum of the second to 



