﻿12 



PLEISTOCENE MAMMALIA. 



6. In II striata and //. brunnca t lie second and third premolars, both upper and 

 lower, are placed with the long axes oblique to the line of the alveolar border, while in 

 II. crocuta this is not so. 



(5) Table op Measurements op the Permanent Teeth. 



Hyana spelaa = crocuta, 



Tor Bryan caves, Torquay (Brit. 



Musj., fig. PI. IV. m. 1 is from 



Wookey Hole. 



:-l 



:'i 



i 



1-75 



1-35 

 63 



0-75 



0-7 

 2-05 



"1 

 |l 



1-85 



1-4 

 2-95 



1-2 



2-5 



1-7 

 4-6 



2-7 



"* 1 



g'| 



4-5 



21 



4-55 



2-4 



-1 



0-5 



0-5 



0-55 



0-4 

 23 



l« 



06 



0-55 

 2-55 



0-9 



08 

 3-fi 



1-C5 



1-35 

 6?! 



1-7 



13 

 2-75 



1-05 



i 



22 



1-55 

 4-5 



2-15 



|a 



2-25 



1-35 

 395 



11 



335 



14 



4-0 



1. Antero-posterior extent at 



base of crown 



2. Maximum transverse 



measurement 



0-8 



0-65 



2'4 



10 



0-7 

 2-7 



1-3 



10 

 4-15 



4. Measurement taken from 

 notch "between roots to top 

 of crown 







(6) Succession of Teeth in Ilyarna. — This subject has been dealt with by Boyd 

 Dawkins, 1 who mentions that in the upper jaw the first tooth to appear is pin. 1. In 

 the lower jaw, to judge by two specimens in the British Museum, c. and i. 1 appear 



first, followed by the large carnassial tooth m. 1, and by pm. 2; the other premolars, 

 pm. 3 and 4, appearing somewhat later. 



Boyd Dawkins mentions that the first teeth to disappear in the adult hyaena are the 

 large bone-crushers pm. 2 and 3, and pin. 3 and 4 ; these teeth are always very 

 much worn in the middle-aged adult, while pm. 1 and pm. 2 show scarcely any 

 trace of wear. 



(7) Distinctive Features of the Deciduous Dentition of the Genus Hya-na. — The 

 formula for the deciduous dentition in Hymna is d.i. f- d.c. \ d.m. f, as in Canis and 

 Ursus, as compared with d.i. f d.c. \ d.m. § in Felts. 



I have not had an opportunity of examining the deciduous incisors, but de Blainville 

 notes that they differ from those of the adult in having the crown quite undivided. 

 There is no noteworthy difference in the canines. The most distinctive teeth are the 

 deciduous carnassials d.m. 3 and d.m. 4. 



D.m. 1. The only example of this tooth that I have seen is that shown in PI. V, fig. 5. 

 The fragment of the upper jaw showing deciduous dentition figured in PI. V, figs. 3, 4, 

 bears no trace of its alveolus. Dawkins 2 describes it as follows : — "Trenchant, conical, 

 and slightly incurved. Its anterior base, narrower than the posterior, bears a small cusp, 

 while the posterior generally exhibits a slight thickening without the cusp. Sometimes, 



Nat. Hist. Kev .,' n. s., v. 



2 Ibid, v, p. 86. 



