SKULL AND CLAWS OF THE FELIDJE. 



11 



SIDE VIEW OF LION ' S 8KULL - 



-"i, auditory meatus: b.ty, bulla tympani; j, jugal arch or zygoma: o.c, occipital 

 condyle for the articulation of the skull with the first vertebra ; c, condyle of the lower 

 jaw ; g, glenoid cavity with which the condyle of the lower jaw articulates : p. the bony 



ci^p, or paroccipitai process. 



vertebral column, large limb bones, &c. All the points mentioned in the introduction to the 

 group as being characteristic of the Carnivorous type of skull are here carried to their extreme. 

 The bony ridges for the attachment of the jaw-muscles are immense ; the jaws attain their utmost 

 limit of structure and strength, and the lower jaw being perfectly incapable of motion from side to 

 side, the teeth, as we shall see by-and-by, 

 act like scissors and not like mill-stones. 



If the skull of a Cat be examined, 

 there will be seen on its under surface, 

 near the hinder end, a pair of rounded 

 swellings, directed somewhat obliquely. 

 On looking at the skull from the side, 

 there is seen to be a roundish aperture, 

 the auditory meatus, leading into each of 

 these swellings, which are found to be 

 thin-walled half globes, stuck on, as it 

 were, to the under surface of the skull. 

 Round the aperture is fixed, in the living 

 state, the Cat's prominent external ear, 

 and stretched across it, like the parchment 

 of a drum, is a thin, membrane, which 

 vibrates with every sound. The rounded 

 cavity is called the "drum of the ear," 

 the membrane stretched across it the 



.. -, . 



drum membrane, Or tympanic mem- 



brane," and the bony half-globe, which 



forms the floor of the drum cavity, is the " bulb of the drum," or bulla tympani. 



Closely pressed against the hinder wall of this bulla is a sort of bony clamp, which seems to keep 

 the bulla in its place, and running obliquely along the surface of the swelling is an indistinct groove, 

 corresponding to which, in the interior of the drum, is a bony wall, dividing the drum cavity into an 

 inner and an outer compartment, these two divisions being formed from separate bones, as an 



examination of a very young skull will 



show. 



The almost globular form and great 



relative size of the bulla tympani; the 



absence of any distinct bony passage 



/ */ JT O 



leading from its cavity to the interior, 

 the opening being quite flush with the 

 wall of the drum \ and the division of the 

 cavity into two parts by a bony partition, 

 are all very important as distinctive cha- 

 racters of the Cat family, and also, with 

 lesser modifications, of the whole ^luroid 

 group. 



The power of retracting the claws, 

 so characteristic a feature of all the true 

 Cats (which are, without exception, digiti- 

 grade), is brought about by certain pecu- 

 liarities of structure of the last two joints of the toes. Of the three pJialanges, or bones which make 

 up the skeleton of the toe, the first, or that nearest to the wrist or ankle, is of the ordinary shape : 

 about three times as long as broad, with a regular cylindrical shaft, and pulley-like ends, for articula- 

 tion with the bone to which it is joined. The second, or middle phalanx, is pretty much like the first, 

 except that its shaft is scooped out on one side, so as to make a greater distance between it and the 

 corresponding bone of the next toe than there would otherwise be. The third and last joint, called 



UNDER TIEW OF LION 8 SKULL. 

 The letters have the same significance as in the side view. 



