HEEPESTES. 169 



the species liave short, rounded ears; the head rather long, and the nose nude 

 and prominent, and marked hy a vertical groove that runs to the upper lip. The 

 legs are rather short, and in all the species they are provided with five claws on each 

 foot. The claws are of variable strength, and they never present any marked modi- 

 fication on the common type, which is that of a fossorial claw. Any departure 

 from the normal type that has been hitherto observed seems to have been entirely 

 due to disuse, the result of the animal having been kept in confinement. The 

 tarsus in its mesial line may either be wholly nude to the heel, or partially clad ; 

 but this character, taken alone, is an unreliable guide to specific afiinity, because 

 two such widely different species as -H". auropunctatus and IS. vitticoUis agree in 

 this detail, while the nearly allied species, _H". pallidus and S. fuscus, are separated 

 by this character of their tarsus. 



In all the species already named, there are 40 teeth, any apparent exception to 

 the rule being satisfactorily explained as a result of age. The dental formula of the 

 milk teeth is f | -f | a ±=S2, and of the permanent teeth | a i. || ||. |=| 0^4,0, 

 and the description of the teeth of one species will suffice to give a general idea 

 of the dental characters of the genus. 



The two middle pair of upper incisors are considerably smaller than the external 

 pair. The upper half of the crown of these teeth, posteriorly, is concave from above 

 downwards, the tip of the crown being laterally rounded. The margin defining this 

 concavity from the basal portion of the crown shows a distinct tendency to form two 

 rounded cusps. The posterior, concave surface of the crown of the second incisor is 

 placed obliquely ; and at the inner margin of the base, or upper end of the concavity, 

 there is a somewhat prominent, mammillary cusp. The canines are well developed, 

 and do not present any special characters. The first premolar is the smallest and 

 shortest tooth of its kind, and is somewhat laterally compressed, the base of the crown 

 forming a slight protuberance posteriorly, which is more developed in some species 

 than in others. The second and third premolars are about the same size, and both 

 have the triangular, pointed crown laterally compressed, with a sharp anterior and 

 posterior border ; the cingulum of the second premolar forms a slight ridge at the 

 base of the anterior border and a more prominent cusp-like eminence at the base of 

 the posterior margin, these portions of the cingulum being more developed in the 

 tliird premolar which is distinguished from the second by the cingulum forming a pro- 

 minent projection, on the inner aspect of the base of the crown, over the most external 

 fang. The fourth premolar is the largest of all the teeth, and is only an intensified 

 development of the characters presented by its immediate predecessor. In this tooth, 

 the inner prominence of the cingulum has become converted into a triangular cusp 

 placed nearly on a line with the anterior margin of the tooth, and the cusp at the 

 posterior aspect of the base of the crown constitutes an oblique, elongated, somewhat 

 bitubercular ridge, whilst the cingulum at the anterior border of the tooth forms 

 a prominent ridge, the triangular central crown of the tooth being broad antero- 

 posteriorly and situated between the inner and posterior cusps. There is a large 

 vacant space internally, between the last premolar and the first molar, for the 



