80 REPORT—1848, 
or where the sphenoidal branch terminated, was not stated. Prof. Bronn had con- 
tended that this so-called ‘arterial perforation’ was the posterior aperture of the 
nostrils in certain fossil crocodiles, and had cited a letter from M. de Blainville ex- 
pressing that anatomist’s conviction of the accuracy of this view. 
Prof. Owen stated that two short grooves converged, from without inwards and 
from above downwards, to terminate in the fossa behind the true posterior nares, in 
which fossa the median aperture in question was situated; both that aperture and 
those grooves led upwards to canals which conveyed air from the mouth to the ear- 
chambers. The canal from the median aperture divides into an anterior (sphenoidal) 
and a posterior (occipital) branch, and each of these divisions bifurcates to the right 
and left to communicate with the tympanic cavities; the occipital bifurcations also 
communicate with the beginning of two other eustachian canals, extending from the 
tympanic cavities to the lower lateral apertures and grooves converging to the com- 
mon median perforation. All these canals open by a common median orifice upon the 
soft palate behind the true posterior nostril. The carotid canals commence by fora- 
mina situated one in each exoccipital bone external to the base of the condyle, and 
open also into the tympanic cavities, through which the arteries pass to enter bony 
canals leading from those cavities to the sella turcica. Examination of the soft parts 
in crocodiles and alligators that had died in the Zoological Gardens, and of the skulls 
of these and of the gavial, had confirmed the correctness of the description of the 
median foramen in question, as the “common terminal canal of the eustachian 
tubes,”’ given in a former ‘ Report’ bythe author. (Reports of British Association, 
1841, p.76.) 
With regard to the homologies of the above-described complex palato-tympanic 
air-passages in the Crocodilia, Prof. Owen stated that the lateral bony canals termi- 
nating in the common median fossa by distinct fissures, answer to the simple eusta- 
chian tubes of chelonians and lacertians, and the median canal with its dichotomy 
into four tubes, would seem to be a peculiar superaddition to the palato-tympanic 
air-passages in the crocodilian order. 
Note on Sounds emitted by Mollusca. By Lieut.-Col. Porriock, F.RS. 
I think it right to draw attention to the Helix aperta, which is very remarkable 
for its property of emitting, when irritated, a strong and well-marked sound. When 
I first noticed the sound thus emitted on accidentally touching the animal, I was 
peculiarly struck by it and immediately referred to Rossmiiesler, who I found de- 
scribes the quality of the animal in a very graphic manner, stating that the sounds 
were such as indicated irritation. The Helix aperta is very abundant at Corfu, ap- 
pearing thickly on the squill leaves in the spring, when about the beginning of March 
the annual increment of growth of the shell is perfectly soft. If the animal be irri- 
tated by a touch with a piece of straw or other light material, it emits a distinctly 
audible sound possessing a singular grumbling or querulous tone. This it frequently 
repeats if freshly touched, and continues so to do for apparently an unlimited space 
of time, as I kept one for a considerable time in my house, and heard this sound 
whenever I touched it. F 
As Rossmiesler has so fully described this fact, I shall only add that I have, on 
more occasions than one, heard what I considered a similar, though very feeble 
sound from the Helix aspersa, and I need not say that the explanation seems very 
easy from the structure of the animal. 
On a new Species of Argonaut, A. Owenii, with some Observations on the 
A. gondola, Dillwyn. By Love.t Reeve, F.LS. 
Among the Argonauts captured by Sir Edward Belcher during the voyage of the 
Samarang, are two species, one distinct from any hitherto described, the other iden- 
tical with a species, A. gondola, described upwards of thirty years since by the pre- 
sident of the Section, Mr. Dillwyn, in his ‘ Descriptive Catalogue of Shells,’ but 
which had been disposed of by subsequent writers as a variety or immaturestate of the 
A. hians or tuberculosa. Specimens of each species were taken alive in the Atlantic 
by means of a gauze net at night. Drawings of the animal were exhibited made by 
