342 REP'iTLIA. 



lating cartilage ; they move on the inside of the lower jaw like a joint ; 

 but that part of the jaw which opposes them is not covered by a 

 cartilage, but with a soft ligamentous substance. There is a very loose 

 capsular ligament 1 , which has an opening at the angle of the mouth 

 as in the drawing 3 of the head. These processes keep the jaw from 

 moving from side to side, so that, as there is no rotatory motion, there 

 is no moveable cartilage. 



As the crocodile has no lips, the teeth are exposed 3 : they are very 

 sharp, something of the shape of a lancet ; the upper teeth stand on 

 the outside of the under ; they are not made for smashing or grinding, 

 but are well fitted for holding ; so that this animal must swallow every- 

 thing whole that it gets into its mouth ; which indeed they do. The 

 posterior nares is one opening with a ridge, which becomes broader and 

 broader, forwards in the nose and at last divides into two. The external 

 nose is a round soft substance on the fore-part of the upper jaw near 

 the lip ; it does not project, and the two nostrils open near the lower end 

 in a semicircular form 4 . The velum palati is opposite to the valve on 

 the tongue, and is half an inch further forwards than the bony palate, 

 so that it arises from the roof of the mouth, is veiy elastic, and com- 

 pletes the stoppage into the fauces 5 . 



The eyelids move equally, so that there is a depressor and elevator ; 

 but the last seems to be inserted pretty near the external angle (but 

 this muscle I am not very clear about), and some of its fibres are lost 

 in the tunica conjunctiva at its external part. The depressor is a very 

 broad muscle, and seems to be inserted both into the membrana nicti- 

 tans and the under eyelid. The course of it is oblique, arising from 

 the internal, or rather what we would call the anterior part of the 

 orbit in this animal ; from thence it passes upwards and a little back- 

 wards. The use must be to depress the under eyelid ; and, as it is 

 inserted into the membrana nictitans and then comes back, it must 



1 [A continuation of the membrane of the mouth.] 



2 [This drawing is in the Museum of the Koyal College of Surgeons, and is 

 engraved in the ' Physiological Catalogue,' vol. ii. pi. 26. fig. 1, «'.] 



3 [Hunt. Preps. Phys. Series, Nos. 380, 388.] 



4 [By a single aperture. In the living crocodile the nose can be slightly raised, 

 and much more so in the gavial.] 



5 [Hunt. Preps. Phys. Series, Nos. 1464—1467, and Phys. Catal. vol. ii. pi. 

 28. The margins of the tongue being tied down to the rami of the jaw, that part 

 of the membrane over the basihyal cartilage is pushed up when this is raised, the 

 tongue itself being immoveable ; when the basihyal is depressed the valve disap- 

 pears. This structure does not relate so much to the act of swallowing the food, as 

 to that of seizing and retaining it under water ; as a defence against the entry of 

 water into the glottis during immersion, and against the intrusion of insects, when 

 on land.] 



