190 MAURICE G. MEHL 
cranial region seems to extend back much farther than in Angis- 
lorhinus; to such an extent, in fact, that the basioccipital is plainly 
visible in a dorsal view in the former. The following table of 
measurements of Angistorhinus grandis may be found useful in 
comparing it with other forms. 
Greatestilengthyon skulls eerie eae eee 077 mm. 
Length of skull from quadrates to tip of rostrum. .go09 
Length from nares to tip of rostrum.............. 590 
Length from anterior borders of orbits to tip...... 755 
Tniter-orbital width ie wee ce ieee ane menace 68 
Greatest width ofjskull-about:<.-55--s--- 420s" 390 
Another specimen of Angistorhinus is represented by a skull, the 
mandible, and apparently a nearly complete skeleton. The pos- 
terior end of the mandible and the upper posterior part of the skull 
are missing, but these may be contained in the unpacked slabs. In 
general appearance this specimen is the counterpart of A. grandis 
though smaller and more slenderly built. It can hardly be con- 
sidered a young individual of A. grandis, however, as some of the 
following differences in the rostrum will show. In the second 
specimen the slender rostrum starts much more abruptly in front 
of the antorbital vacuity than in A. grandis. While the smaller 
skull is considerably compressed laterally, and lateral measurements 
are, therefore, of less value than longitudinal ones, the rostrum 
seems but little affected by this compression and the following 
measurements seem to show the differences well. At a point 140 
mm. in front of the antorbital vacuity the width of the rostrum is 
about 56 mm. (some allowance is here made for compression), 
while at the same distance in front of the antorbital vacuity in A. 
grandis the width is about 94 mm. This is exactly the opposite of 
what one would expect if the former specimen were but the young 
and the latter the adult of the same species. In A. grandis the 
terminal expansion is just back of the downward extension and the 
expanded portion includes but four teeth. In the smaller specimen, 
however, the expansion takes place suddenly just back of the second 
tooth behind the downward extension and from this point to the 
extremity the lateral outlines of the rostrum are approximately 
parallel. Eight teeth are included in the anterior expanded part 
