522 PROFESSOR OWEN ON THE EUSTACHIAN CANALS IN CROCODILES. 
generally as communicating with the palate by a wide and short canal (p. 511). 
But in a supplementary paragraph to Cuvier’s description of the foramina in the 
base of the skull of the Crocodile, the osseous aperture of the Eustachian tube is 
stated to be perforated in the exoccipital, near its junction with the basioccipital, and 
to be situated below the anterior condyloid foramen*. 
In the ‘ Report on British Fossil Reptiles,’ communicated to the British Associa- 
tion in 1841^, I described the foramen in the basioccipital, e, as the common 
terminal canal of the Eustachian tubes, and the foramen in advance of it, «, as the 
posterior aperture of the nasal canals. 
In the ‘ Abhandlimgen liber die Gavial-artigen Reptilien des lias-formation,’ fob 
1841 , by Professors Bronn and Kaup, it is argued at great length (pp. 12, 16,24) that 
the median foramen, e, is the true posterior aperture of the nostrils ; and a letter 
from Professor De Blainville, dated December 8th, 1841, is cited by those authors 
in support of their view, in which letter Cuvier’s determination, that it was ‘ an 
arterial foramen,’ is rejected, and Professor Bronn’s opinion is stated to be completely 
confirmed by the appearances in the original fossil skull of the Teleosaurus from Caen, 
described and figured by Cuvier. 
Besides the median foramina above specified, there are several lateral foramina, in 
symmetrical pairs, in the same part of the base of the skull of the Crocodile. One on 
each side the base of the condyle, Plate XL. fig. l,p, is the ^ precondyloid foramen,’ 
which gives exit to the hypoglossal nerve : external to this is a larger foramen, f, 
through which pass the eighth pair of nerves and a vein from the tympanic cavity ; 
below these, and still in the exoccipital (2), is the foramen, c, described by the con- 
tinuators of Cuvier as the bony outlet of the Eustachian canal ; and still lower 
down, in the suture between the basioccipital (1) and basiphenoid (5), is the fora- 
men, el, which I have not found noticed by any anatomical author. 
The decisive test of the nature of these latter foramina, el, and of the different 
opinions respecting the foramina, c, c, and the median foramina, e and n, was, of 
course, to be sought for in the results of an accurate anatomical examination of the 
parts in the recent Crocodile. I have, accordingly, availed myself of the opportuni- 
ties liberally afforded to me by the Council of the Zoological Society, to dissect for 
this purpose specimens of an Alligator {Alligator liicius) and a Crocodile {Crocodilus 
acutus) which have died at the Zoological Gardens ; the examination being made 
after injecting the vessels of the head with coloured wax. 
The entocarotid arteries (Plate XL. fig. 2, c) enter the foramina (fig. 1 c, c) situ- 
ated, one in each exoccipital bone, 2, at the side of the base of the condyle, below 
* “ Le trou condylo'idien est dans I’occipital lateral, et en dehors de lui est un trou assez grand pour des 
Taisseaux. L’ouverture osseuse de la trompe d’Eustache est au dessous des precedents, aussi dans I’occipital 
lateral, et tout pres du point de reunion de cet os avec le basilaire et le sphenoide.” — Lecons d’Anat. Comp, 
tom. ii. p. 524, 1837. 
f Reports, 8vo, p. 96. 
