430 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 7, 



tooth has a compressed, pointed crown, scarcely half the height of 

 the canine and two-thirds as broad at the base, with a ridge along 

 the inner side of the base, and a more developed posterior basal tu- 

 bercle : it is divided by a small interval from the canine. The second 

 molar, with a slight increase in size and a similar shape, has the fore 

 part of the basal ridge developed into a low point, and the hinder 

 tubercle is relatively larger and more pointed. The third tooth is 

 larger than either of the two preceding, but resembles them in form. 

 The fourth, with the same antero-posterior extent, has a lower crown, 

 the middle cusp being relatively shorter, but both the anterior and 

 posterior ones are larger, and now begin to assume the character of 

 independent cusps ; their bases almost meeting upon the inner side 

 of the base of the middle cusp. The fifth molar, with a slight in- 

 crease of size, shows a still further development of the accessory cusps, 

 which now are inclined backwards, or project from a more internal 

 plane than the middle cusp. The impressions of the succeeding teeth 

 show that their middle cusp was longer in proportion to its basal 

 breadth ; and thus agree, like the foregoing teeth, with the teeth simi- 

 larly marked in fig. 10. The canine-like tooth seems to have a bifid 

 fang ; the three succeeding premolars, implanted each by two fangs, 

 in this respect, as in their general form and proportions, resemble the 

 four premolars of the lower jaw of the Mole. The ramus of the jaw 

 very closely resembles in shape that of the Mole, but is larger than 

 that of the Talpa eiiropcea, being 1 inch 3 lines, or 32 millimetres 

 in length, that of the Mole being 1 inch, or 25 millimetres. The 

 crown of the laniariform tooth is relatively longer, and the fourth 

 tooth counting therefrom is of a different form, being of much 

 smaller size and of a more simple structure than is the corresponding 

 tooth which forms the first true molar of the Mole. The greater 

 number of molar teeth indicated in the present and displayed in 

 other specimens of the Spalacotherium decisively demonstrate not 

 only its specific but generic distinction from the Mole, or any known 

 existing insectivore ; the marsupial Myrmecobius being the sole 

 mammal, with incisors and canines, that resembles the Spalacothere 

 in the excessive number of the molar teeth. Fig. 11 « is a magni- 

 fied view of the teeth 4 & 5, showing the meeting of the accessory 

 cusps on the inner side of the crown. 



In the specimen marked a 7 in Mr. Brodie's series, and represented 

 in fig. 1 2, the tooth, h, that immediately precedes the large canine- 

 shaped tooth, c, is preserved ; it is also canine-shaped, but about half 

 the size of that tooth. There is a trace of a small incisor in the 

 crushed and broken anterior end of the jaw in front of the above 

 teeth. This specimen the more inclines me to the belief that the 

 larger canine-shaped tooth is the first premolar, as in the Mole ; but 

 it appears to be implanted by a simple expanded base in the present 

 specimen : the crowns of the three succeeding teeth, and the fractured 

 bases of the crowns of the four or five following molar teeth are 

 shown in this mutilated portion of the right ramus of the lower jaw 

 of the Spalacothpriuni. Fig. \2ci is a magnified view of two of these 

 teeth, from which the middle and hind cusps have been broken away. 



