[LAMBE] ON A NEW CROCODILIAN GENUS 223 
shown in plate I, fig. 2 and by a smaller specimen (cat. No. 1775a) not 
figured. ‘The alveolar border above is broadly undulating in curves 
that are more pronounced than in the living alligator (Caiman latiros- 
tris). The dentary is constricted in the neighbourhood of the eighth 
tooth; in advance of this it expands horizontally inward and outward, 
attaining its greatest anterior breadth in line with the centre of the 
fourth tooth; posterior to the constriction the alveolar border rises in 
a broad convex curve to the position of the twelfth tooth adding con- 
siderably to the depth of the dentary whose upper border then continues, 
parallel to the inferior surface, in an almost horizontal line to the 
eighteenth tooth. The front tecth, the first to the fourth, were di- 
rected obliquely outward, the first and second particularly so, the other 
teeth had a decided inclination outward up to about the twelfth, back 
of which a more upright position was assumed. The reader’s attention 
is drawn to a similar outward inclination of the front teeth of the 
mandible of Diplocynodon gracile, Vaillant, from the Lower Miocene 
of St. Gérard le Puy (Allier,) France. 
The mandibular symphysis is short and contributed to by the 
dentary and splenial together, its posterior end being in line with the 
hinder edge of the alveolus for the sixth tooth. The splenial enters 
into the formation of the symphysis to the extent of about one-fifth of 
the latter’s length. 
A groove (Meckel’s), enclosed outwardly by the splenial, channels 
the inner surface of the dentary at its mid-height, (dg, plate I, figs. 
la, 1b and plate III, figs. 1e and 2a). It passes, in its more anterior 
course, from beneath the splenial forward along the symphysial surface 
as far as a point opposite the division between the third and fourth 
teeth. The exit of the dentary groove from under the splenial is made 
through a transversely oval orifice (3.5 mm. wide and 2 mm. high) 
at the anterior end of this bone in the suture between it and the dentary 
(o, plate I, fig. 1a). The opening is bounded principally by the sp!enial, 
the groove in the dentary being here shallow. Thus, anterior to the 
two splenial elements of the mandible, the dentary grooves of the 
rami meet and are continued forward in the symphysial surface as a 
tubular channel between the dentary bones with its termination at 
about the mid-length of the symphysis. The symphysial surface of the 
splenial is rugose, that of the dentary is comparatively smooth. Behind 
the symphysis, the splenial, which is here thin with a convex outer 
surface, is pierced by a longitudinally elongated foramen (f, plate J, 
fig. la) that opens into the Meckelian groove. On removing the splenial 

Ann. Sci. Géol. vol. III, art: 1, p. 18 (1872). 
