FAUNA OF THE KARNUL CAVES. 
37 
Hystrix crassidens, n. sp., nobis. 
Definition. — This form 1 is considerably larger than If. Mr sutir osiris , from which 
it is also distinguished by the circumstance that the upper incisors are much wider 
than the lower. 
Upper incisors. — The extremities of a pair of upper incisors are figured in pi. 
VIII. fig. 19 ; another left tooth being represented, from the lateral aspect in fig. 20. 
The measurements of the latter and of an upper incisor of H. Mrsutirostris are as 
follows. 
B. crassidens. B. Mrsutirostris. 
Antero-posterior diameter 0-44 0-30 
Transverse do. 0-32 0-22 
Mandible. — The left ramus of a complete immature mandible is figured in pi. 
VIII. figs. 17, 17a ; mm. 4 is still in situ , m.3 has not come into wear, and the incisor 
is pushed partly out of its alveolus. The contour of this specimen agrees very closely 
with the mandible of If. Mrsutirostris , but the space occupied by the molar series is 
longer ; the latter feature being still better exemplified in a rather older example 
represented in fig. 16, where m.3 is more protruded, and pm. 4 is seen in alveolo. In 
the latter specimen the length of the space occupied by the three true molars is 1 - 22 
inches, the corresponding length in a somewhat older example of H. Mrsutirostris 
being 1*05 inches. The incisor of the figured mandible agrees in width with that of 
the living species, and is much narrower than the upper incisor of the fossil, and 
since the same feature is exhibited by all the lower fossil incisors (the extremities of 
a pair being represented in fig. 21), it may be taken as a character of the species. 
The concave surface of the lower incisors of the fossil is less narrowed than in 
the living species. The dimensions of the recent and fossil lower incisors are as 
follows. 
U. crassidens. H. Mrsutirostris. 
Antero-posterior diameter 0-32 0-28 
Transverse do .' 0’25 0‘26 
Cheek-teeth . — Beyond their superior size it does not appear that the cheek-teeth 
of the fossil can be distinguished from those of the recent species. 2 A detached 
right upper premolar is represented in fig. 1 8 to show the large dimensions which 
these teeth attain, the antero-posterior diameter of the base of the crown being 0'5 
inch. 
Humerus. — A specimen of the right humerus, wanting the proximal epiphysis, is 
represented in pi. VIII. fig. 6 ; it is of considerably larger size than the corresponding 
bone of H. Mrsutirostris , from which it is also distinguished by the shorter deltoid 
ridge (dr). 
Distinctness and affinities. — The difference in the size of the upper and lower 
incisors appears to be a character by which the Karnul porcupine is distinguished 
1 Referred in ‘ Rec. Geol 1 . Surv. Ind.’ vol. XIX. p. 120. to S. Mrsutirostris. The -writer follows Prof. Flower in 
adopting the latter name in place of II. leucura. 
2 The narrowness of the true molars in the specimen represented in fig. 17, 17a is due to their very early stage of wear. 
