264 



ANIMAL PHYSIOLOGY. 



[LESSON 80. 



(i, i) placed above the muscular foot. Behind these are two sym- 

 pathetic ganglia (k), which send filaments to the digestive organs. 



1195. In the simple form of the nervous system presented by the 

 Carinaria Mediterranea (Fig. 380), there is a close analogy with 

 the ordinary disposition of the symmetrical detached nervous columns 

 along the ventral surface of the abdomen in the inhabitants of bi- 

 valve shells. Lobed ganglia (g, h) are found in this animal at the 

 sides of the resophagus, and a transverse nervous band (i) connecting 

 them, and encompassing that passage. From this nervous cesopha- 

 geal ring (i) the two optic nerves pass laterally to the eyes (/,/), 



Fig. 379. 



Fio 



Nervous system of Bulla lignaria. Nervous system of Carinaria Mediterranea. 



and the tentacular branches pass upwards and forwards to the long 

 slender tentacula (e, e). Numerous branches extend downwards and 

 laterally, to ramify on the muscular parietes of the abdomen, and 

 two principal trunks (k, k), extending backwards along the ventral 

 surface of the abdomen, meet with a large compound quadrilobate 

 (four-lobed) ganglion (q) behind the stomach, and above the di- 

 verging muscles of the compressed foot. These two ventral (belly) 

 detached and converging columns (&, A), extending from the oeso- 

 phageal collar to the middle or pedal ganglion (q), can be traced 

 backwards from these ganglia, along the lower surface of the ab- 



