The anatomy of Lucapina crenulata. 

 Heart 



467 



Buccal aorta 



Genital aorta 



Palliai Neural Pedal 

 artery arteries arteries 



Gonad Stomach 



Right nephridium 



Palliai sinus Pedal veins 



Wall of 

 oesophagus 



Basibranchial sinus 



Ctenidia 



Heart 



side is the rather large nerve extending into the tentacle, within which 

 it splits up into many smaller nerves running parallel in the tissue. 



Behind the base of the tentacle nerve is the much smaller one 

 that supplies the eye. By a series of sections longitudinally through 

 the eye, it is possible to follow this nerve to its terminations, and 

 also, from nitric acid preparations one is able to dissect out the eye 

 with its nerves as shown in Fig. 13. After going a short distance 

 into the ocular tubercle the nerve divides into several branches. Some 

 of these go to the muscles and epithelial cells but four of the largest 

 pass directly to the eye, where they appear to spread out into a 

 ganglionic cup which surrounds the eye-ball with the exception of the 

 front. The cells of the retina are apparently attached directly to this 

 ganglionic layer. P. Fraisse (in : Z. wiss. Zool., V. 35, tab. 25, tig. 3) 

 has figured a section through the eye of Fissurella graeca. If the 

 optic nerve (o) were divided into four parts, and attached further up 

 on the sides of the eye-ball, this figure might do for Lucapina 

 crenulata. 



Two nerves (N.w) are given off to the walls of the neck, from 



