GASTE110P6DA OF THE UNITED STATES. 4T 



Lranclics to tlic ihuscular peritoneum ; 7th, brandies 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 

 s'ldc, — Ist, a nerve to the external muscular structure 

 of tlie buccal body ; 2d, two branches which penetrate 

 posteriorly into the buccal body ; ^5d, 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. 



Tho above distribution of the nerves has been princi- 

 pally derived from dissections of Glandina and JIdix 

 alhnlahrh. In the former genus, upon what is the nerve 

 to tho inferior tentacle in tho other genera, there is 

 formed, near the base of the tentacuhx), a ganglionary 

 enlargement, from which passes off the true, inferior 

 tentacular nerve of this animal, and two other large 

 branches to tho third, or external tentacle. 



The nervous centres are composed of ganglion glo- 

 bules, varying very much in size ; some arc very large, 

 others are not more than onc-eiglitli the diameter of 

 tlic larger ones and nuclear bodies. Tho globules are 

 more or less polygonal, fi'om mutual pressure, arc dis- 

 tinctly granular, and contain a nucleus whicli is com- 

 paratively of enormous size. The latter usually fills 

 one-half or two-thirds of the cell or glo1)ule, is more 

 distinctly and darkly granular, and contains from one 

 to seven small, round, transparent nucleoli. The sepa- 



