TRANSACTIONS. 185 
understanding the physiology of this curious mouth. I think that 
the jaw is used to snip off portions from the edge of the leaf, and by 
the action of muscles on the cartilage under the ribbon it is 
drawn to the front of the mouth, turning the teethy sac inside out 
to rasp portions from the flat side of the leaf, or it may be used to 
rasp the leaf when held by the jaw. Behind the buccal mass 
there is a short cesophagus, through which the food passes to the 
crop, which is used asa store. It then enters the stomach, when 
after digestion and mixing with the secretion from the liver, it 
passes on to the bowel and the vent, which opens externally by 
the side of the respiratory orifice. | When examining the con- 
tents of the bowel I found a great number of small intestinal 
worms, or entozoa. 
Nervous System.—Surrounding the cesophagus is a collar of 
nerve tissue, which may be called the large nerve centre or brain 
of the animal. It is divided into two divisions—the sapra- 
esophageal ganglia; and the sub-esophageal ganglia. Both are 
united by bands of nerve fibres. The supra-cesophageal ganglia 
(which in some measure corresponds to the cerebrum of the higher 
animals) give off the principal nerves to the head segment, eyes, 
&c., the first pair going to the inferior antenne. We know that 
in the higher animals the first pair are the special nerves of the 
sense of smell, and if we reason here by analogy we will call the 
smaller antenne the organs of smell. The second pair are the 
optic nerves. The third supplies the retractor muscles of the eye, 
a branch going to the retractor of the head. The sub-cesophageal 
ganglia are divided into two portions—an anterior and posterior 
portion, the anterior giving nerves to the muscular substance 
of the foot, &c. The posterior gives branches to the body wall, 
viscera, &c. The beautiful silvery appearance of the nerves radi- 
ating from the large nerve centre is very striking, and when once 
seen is never forgotten. 
Generative Organs.—This slug, like many members of this 
order, is hermaphrodite, ze. it is both male and female, but not 
self impregnating. The common orifice is under the fold of the 
mantle in front of the vent. The organs consist of vagina ; vaginal 
prostate; receptaculum seminis ; albuminiparous gland; penis sac; vas 
deferenes ; hermaphrodite gland, with its duct. The principal organ 
is the gland, which is situated in the left lobe of the liver. It 
consists of numerous follicles of a darkish colour, held together by 
connective tissue. The ova and spermatosoa are both formed in 
