242 INTRODUCTION. 
branches to the muscular peritoneum ; 7th, branches to 
the origin of the tentacular retractors ; 8th, branches 
to the oviduct, ovary, testicle, stomach, intestine, and 
liver. 
From the stomato-gastric ganglia pass off on each 
side, — 1st, a nerve to the external muscular structure 
of the buccal body ; 2d, Wo branches which penetrate 
posteriorly into the buccal body ; 3d, a branch to the 
salivary duct and gland ; 4th, a branch to the oesophagus 
and stomach ; 5th, branch to the interior of the buccal 
body anteriorly. 
The above distribution of the nerves has been princi- 
pally derived from dissections of Glandina and Helix 
albolabris. In the former genus, upon what is the nerve 
to the inferior tentacle in the other genera, there is 
formed, near the base of the tentacular, a ganglionary 
enlargement, from which passes off the true, inferior 
tentacular nerve of this animal, and two other large 
branches to the third, or external tentacle. 
The nervous centres are composed of ganglion glo- 
bules, varying very much in size ; some are very large, 
others are not more than one-eighth the diameter of 
the larger ones and nuclear bodies. The globules are 
more or less polygonal, from mutual pressure, are dis- 
tinctly granular, and contain a nucleus which is com- 
paratively of enormous size. The latter usually fills 
one-half or two-thirds of the cell or globule, is more 
distinctly and darkly granular, and contains from one 
to seven small, round, transparent nucleoli. The sepa- 
