460 PEOFBSSOE J. ANDERSON ON THE 



external cusp, and between the two internal cusps, is a small conical tubercle (the 

 ridge of Huxley and Mivart in Erinaceus), that for its size and characters merits to be 

 regarded as a cusp. It is not a ridge, but a distinct fifth cusp, situated in the locality 

 I have indicated; and in a skull of an Indian Erinaceus before me it forms a well- 

 marked cusp in the same situation. The second molar is the same as the first, only 

 smaller, and without the median cusp (ridge), which, however, is represented by a 

 ridge connecting the postero-external to the antero-internal cusp. The third molar is 

 still smaller than the former, with the cingulum less developed externally, and only 

 one internal cusp, = tricuspidate. The antero-external cusp is the same as in the pre- 

 ceding molars ; but the postero-external cusp is externally broad, and about twice the 

 breadth of its fellow before it, and its apex shows an obscure notch, which would seem 

 to indicate that it has resulted from union vdth the postero-internal cusp. The 

 solitary internal cusp has all the characters of the antero-internal cusps of the two pre- 

 ceding molars. That the premolars and other molars of this curious insectivorous 

 mammal should have such a remarkable resemblance to the corresponding teeth of 

 Erinaceus, and that its last molar should differ so much from the same tooth of that 

 form, is very remarkable. The first incisors of the lower jaw are widely different in 

 form from those of the upper jaw. They have cylindrical fangs, terminating in laterally 

 expanded, shovel-like crowns, compressed from before backwards, slightly convex ex- 

 ternally and concave internally. The second incisor has a strong resemblance to the 

 first, but the crown has not quite the lateral expansion of that tooth. The posterior 

 margin, a little above the neck of the tooth, is marked by a very minute process, which 

 becomes intensified in the same position in the tooth posterior to it, where it is evi- 

 dently the product of the cingulum. The crown of the third incisor is also laterally 

 compressed, somewhat oval in outline, and is set on unequally to the fang, projecting 

 anteriorly more in advance of the shaft of the tooth than posteriorly. The margin of 

 the crown posteriorly above the neck bears a well-marked process. The canine partakes 

 of the characters of the lower incisors in its compressed character from without inwards, 

 and general form. The crown above the neck is slightly contracted ; but it expands 

 and terminates in a more truncated point than the first incisor. Its siu'face, along the 

 posterior margin, is markedly concave. The first, second, and third premolars are the 

 smallest teeth in the lower jaw, and they have all one form, the middle tooth being the 

 smallest of the three. They are more or less compressed laterally ; and the first is set 

 obliquely in the jaw like the teeth preceding it ; but the second is less so, and the third 

 is nearly vertical. The crown of the first is small and conical, with a cusp nearly as 

 large as itself projecting forwards from its anterior margin, and another, and smaller, 

 posteriorly, the product of the cingulum. In the second the crown is merged in the 

 anterior cusp, so that the external outline of the crown is rounded, with only the 

 posterior cusp developed. The third has a slightly recurved, small, short, conical 

 crown, with an anterior and a posterior cusp. The fourth premolar is the most verti- 



