23 LAWSON, ON LIMAX MAXIMUS. 
apparatus which I could set down to their credit, up to this 
time my efforts have been unsuccessful. From this cireum- 
stance I am led to suspect that in this creature no auditory 
mechanism really exists, and this suspicion is somewhat 
strengthened by the fact, that, the so-called ear-vesicles are 
said to be among the first detectable organs in the embryo, 
which I should not suppose probable as regards an appendi- 
cular mechanism or sense-capsule. ‘To speak more plainly, 
if we were informed, that, in the embryonic life of a verte- 
brated animal, the most well-marked system was the auditory, 
should we not be inclined to fear there was some blunder in 
either the statement or the observation? And, besides, if 
the otolitic capsules be locatedupon the lower nervous centres, 
as is asserted, and thus virtually buried in the viscera, how 
are the sonorous impressions to be received from without ? 
Surely, this would not be an advantageous arrangement of 
parts, nor in obedience to the simplest laws of acoustics. 
For the only method by which a vibration could be conducted 
to the receiving vesicle would be through the mouth and 
cesophagus, so that the familiar expression ‘ swallow” should 
not be at all inapplicable. 
Organ of Touch.—Some state that the tactile sense is 
resident in the inferior tentacula, these being, according to 
the same authorities, provided with bulbous enlargements 
similar to those of the upper ones. Respective of their func- 
tion I can offer no comment, but I cannot just now endorse 
the opinion that nervous expansions exist here ; an enlarge- 
ment of some kind is occasionally observed, but I am not 
prepared to admit its nervous character. Moquin-Tandon* 
attributes to these tentacles the sense of smell. 
Taste.—This faculty, I am disposed to thins, resides in the 
rugose integument forming the lateral boundary of the mouth ; 
this portion of the labial organs is supplied on each side with 
a branch of the inferior tentacular nerve, and here a peculiar 
and interesting nervous arrangement may be observed. The 
branch, on reaching the tegumentary fold alluded to, widens 
as it approaches its extremity, and terminates in a pectinate 
expansion, which is imbedded in the delicate skin of the lip ; 
this comb-shaped structure results from the division of the 
final portion of the filament for about + inch distance into 
a series of minute twigs, which pass off on either side, and 
become lost in the neighbouring tissue. 
* ‘Histoire naturelle des Mollusques terrestres et fluviatiles,’ tome i. 
