646 Doubts respecting 



condyle, a large process for the insertion of muscles situat- 

 ed obliquely within and behind. 



But it is the dental formula of the insectivorous marsupials 

 which more particularly demands our notice. 



In the first place the three sets of teeth are as distinct in 

 disposition as in form ; the incisors being separated from the 

 canines by a space as large as that which divides the latter 

 from the molars. 



The incisors, which are generally very small, are terminal, 

 and grouped together to the number of three or four at the ex- 

 tremity of the jaw, in a nearly straight and transverse line; 

 they have each only a single root, and the crown, though 

 rather diversiform, is never pointed nor conical, but is more 

 or less broad at the extremity. 



The canine, which is always completely isolated, has the 

 usual conical form, a little compressed, widened at the base, 

 and rather strongly arched and pointed at the apex. 



The molars, to the number of seven in the whole, consist 

 of three false and four true. 



The first of the false or "avant-molaires" is often separated 

 from the other two by a greater space than that between the 

 rest ; the remainder, though often rather unequal, present the 

 same general shape, each having two conical diverging roots, 

 and the crown rather compressed, triangular, with a single 

 triangular tubercle, having an indication of a very small lobe 

 in front, and a more distinct posterior process {talon) occupy- 

 ing a lower position. 



The four true molars, including the principal and three 

 hind molars, form an evenly serrated continuous series of sub- 

 equal teeth, of which the largest is usually the last but one, 

 and sometimes the last ; and the first is always the smallest. 

 They are a little thicker across than from back to front, and 

 approach more or less to a parallelogram in shape ; the crown 

 is always divided, as in the Insectivora, into two parts, se- 

 parated by a deep notch, — the one anterior, and in general 

 more elevated, prismatic, and always with three tubercles, 

 one of which is external and two internal ; — the other poste- 

 rior, almost equal, and with two tubercles, one external and 

 the other internal : so that the crown has five tubercles, more 

 marked however in the last tooth but one than in the others. 



As to the roots, though they appear to be only two in num- 

 ber, one for each portion of the crown, as they are much wid- 

 er in the transverse direction than in the other, it is evident 

 that each, dividing itself into two, is certainly not conical. — 

 It must also be farther observed, that these roots are hardly 

 half as long again as the crown, which encroaches considera- 



