Class 6. Mammalia. Order 8. Carnivora. 515 



to the seven lower molars, both the first two and the last two are 

 absent. The tubercular part of the series is almost completely 

 atrophied, for not only are the molars (with the exception of the 

 rudimentary one of the upper jaw) absent, but the tubercular part 

 of the lower sectorial has also disappeared. In Bears, the opposite 

 extreme is reached ; the tubercular teeth are all present, and like the 

 posterior (tubercular) portion of the lower sectorial, extraordinarily 

 well developed, whilst the first three premolars are small, and some 

 fall out with maturity. For other groups see the special descriptions 

 and Fig. 413. 



The milk dentitions are still more nearly ooinoident, since witt one 

 exception (see below), three premolars are present in each jaw, viz,, the second, 

 third, and fourth ; the second upper interdigitates with the second and third 

 lower, the third is exactly like the upper permanent sectorial, the fourth in the 

 upper jaw is a tubercular tooth, in the lower jaw, a sectorial.* It is remark- 

 able that the sectorial of the permanent dentition does not occupy the 

 same position as does the milk sectorial, but in both upper and lower jaws, is 

 one place further back. Only where the number of premolars is less than 

 three (in the lower jaw of the Oat), is the number of milk molars less than the 

 typical number ; the milk molar corresponding with the absent premolar (the 

 second) is then also wanting. 



The last phalanx of each toe bears a claw which is often much 

 curved and can be turned upwards by means of an elastic ligament 

 passing from its phalanx to the penultimate ; so that in some animals 

 [e.g., the Cat) it does not touch the ground in walking (retractile 

 claws). The first digit is usually smaller than the others, and is 

 frequently absent from the hind limb. These animals are either 

 plantigrade, or digitigrade. The clavicle is poorly developed or 

 absent. Placentation zonary. In many forms there are, in the 

 region of the anus, glands or glandular pits, whose secretion has an 

 ofBensive odour. 



Most of the Carnivora are of medium size, and feed either upon 

 other animals, or upon plants (succulent roots, berries, etc.). They 

 occur all the world over (with the exception of Australia), and are 

 most abundant in the Tropics. 



The Oarnivora form three large natural groups, one of which (Cynoidea) 

 includes the Dogs, another (Arctoidea) the Bears, Raccoons and Martens, a third 

 [Mlwroid.ea) the Cats, Viverras, and Hyienas. The differentiation is shown chiefly 

 in numerous minute points in the skull, a full account of which would, however, 

 involve so much detail, that this bare statement must suffice. 



1. The Dog Family (Canidx). _pf,mf ; the tubercular portions of the 

 molars are of medium strength. Head long, tail long, legs long, with five toes 

 in front, four behind; digitigrade. To this family belong the Fox {Canis 

 vulpes), the Polar Foxf (C. lagopus), both with perpendicular pupils; the 

 latter an inhabitant of the Arctic regions: the Wolf (0. lupus), with round 



* In the milk dentition of Carnivora there is therefore the same number of 

 tubercular teeth as in the permanent dentition of the Cat, i e , 4. 



I In the Fox there are usually m |. 



L L 2 



