DAWKIXS ON THE DENTITION OF HY^NA SPELiEA. 87 



from each other by a deep cleft, beneath which, on the inner side, 

 is a broad and shallow depression. The posterior blade is the larger 

 and in this point contrasts with the homologue in H. striata, in 

 which species they are snbequal. Its posterior aspect is traversed 

 by a descending ridge, which, more or less notched immediately above 

 its junction with the tubercular portion of the tooth, offers a rudi- 

 ment of the accessory cusp so strongly developed in the representa- 

 tive molar 1 of H. striata. The tubercular portion is large and 

 well developed, consisting generally, as in the jaw figured, of three 

 small snbequal cusps placed transversely and separated from the pos- 

 terior blade by a broad smooth area. It is, however, subject to con- 

 siderable variations in size and form, sometimes as in one on the table 

 as I write (fig. 3), all three cusps are suppressed, and the ridge which 



Fig. 3. 



takes their place is cleft posteriorly, giving the tubercular portion a 

 slightly bilobed appearance. In fig. 21, PL vi. of the Eeliquise Dilu- 

 viansB, the latter appears to be the result of the development of the 

 two lateral at the expense of the median cusp. This characteristic is 

 deemed by MM. Croizet and Jobert of specific value, and to have 

 belonged to a species which coexisted with the Spelaean Hyaena in 

 Auvergne, and which they term JEE. Perrieri.* "Whether or no this 

 difference be sufficient to map off a distinct species, will be discussed 

 in the description of its permanent analogue, in which it also is 

 present in three specimens from "Wookey Hole Hyena-den. 



The annexed table of measurements, taken at the base of each 

 tooth, in decimals of an inch, gives the relative size of the milk series 

 of the Spelaean Hyena, as compared with that of H. striata. 



The antero-posterior extent of the milk series of the upper jaws, 

 in S. striata is 1*52 inches, in S. speleea given below, 1*53, in that 

 figured 1*57, while that of the lower jaw measures respectively, 1-62, 

 1-86, and 1-63 inches. 



* Op. cit. p. 174. 



