214—6 INDIAN TERTIARY AND POST-TERTIARY VERTEBRATA. 
perfect crania from the Siwalik Hills, belonging to variously aged individuals of the 
present form ; and as those which are immature are more complete than those which 
are adult, the former may be first noticed. The most perfect specimen (No. 39795) 
is the one represented in plate XXVIII. figs. 1, la (of one-third the natural size),^ 
which belongs to a half -grown individual. In general contour, and especially in the 
relative shortness of the palatal aspect of the premaxillse, this specimen agrees 
more closely with G. jpalustris and C. siamensis than with any other recent or fossil 
crocodile, and comparisons may therefore be restricted to those two species. Com- 
pared with half -grown crania of C. palustris (plate XXIX. figs. 1, la) the fossil 
differs by the smaller degree of concavity and the relatively greater width of the 
interorbital bar, although this is shorter than the long diameter of the orbiP ; by the 
relatively greater length of the upper surface of the premaxillse, which is greater 
instead of less, than the length of the narial aperture ; and by the smaller develop- 
ment of the preorbital rugose nodules, and the greater depth of the sculpture on the 
premaxillge. The greater relative length of the upper surface of the premaxillae 
causes the centre of the narial aperture to be situated considerably behind the notch 
for the fourth mandibular tooth, instead of some distance in advance of it. On the 
palatal asjDect the maxillo-premaxillary suture forms a blunt inverted V and extends 
as far back as the sixth dental alveolus, whereas in equal-aged specimens of 
G. palustris (pi. XXIX. fig. la) it usually runs straight across the palate and does 
not extend behind the anterior border of the fifth, although there are occasional 
instances where it reaches the anterior border of the sixth alveolus. 
The next specimen (No. 39796) comprises the anterior portion of the cranium 
and mandible, and has the same general characters as the preceding. The third 
specimen (No. 39797) comprises both the cranium and mandible; and although the 
maxillo-premaxillary suture is not visible on the palatal aspect, the specimen agrees 
in all other characters with No. 39795, the relatively great width of the interorbital 
bar being very well marked.® The fourth specimen (No. 39798), which likewise 
comprises the greater part of the cranium and mandible, is represented^ from the 
lateral aspect of one-fourth the natural size in plate XXVIII. fig 3 : it agrees with 
the foregoing specimens in all essential characters (especially those of the pre- 
maxilla and interorbital bar), but the anterior part of the cranium is relatively 
broader. The concavity of the facial profile, which is a character common to the 
Siwalik form and G. palustris, is well-shown in this specimen. 
An unnumbered palatal specimen belonging to a rather older individual agrees 
with the preceding specimens ; the maxillo-premaxillary suture extending as far 
back as the sixth alveolus, and the facial aspect of the premaxillse being considerably 
longer than the external narial aperture. 
1 The specimen is also figured in “ Falconer’s Palaeontological Memoirs,” vol. I. pi. XXVIII. figs. 2, 3. 
2 In the fossil the two diameters are 1'6 and 2’0 inches ; and in the figured cranium of C. palustris 1’4 and 2’2 inches. 
3 The width of the bar is 1‘9 and the length of the orbit 2‘2 inches. 
4 Also figured in ” Falconer’s Palaeontological Memoirs,” vol. 1. pi. XXVIII. fig. 1. 
