144 A - J- CARLSON. 



My own work was done on the two slugs, Liinax maxiinus and 

 Ariolimax colmnbiamis and on the snail Helix (Ariontci}. In 

 Liinax (PI. VII., Fig. 17) the pedal and pallial ganglia are fused 

 into one ganglionic mass situated ventral to the oesophagus and 

 connected with the supracesophageal ganglion by a commissure 

 on either side of the oesophagus. This pallio-pedal ganglion is 

 pierced by the cephalic artery ; the portion of the ganglion dorsal 

 to the artery is the pallial ganglion proper. This dorsal portion 

 of the ganglion gives rise to four nerves. The two lateral ones 

 (i, 2), which are the stoutest, pass to the pallial complex and the 

 mantle. Besides the mantle nerve, the left side of the ganglion , 

 gives rise to two smaller nerves, one of which takes a posterior 

 direction close to one of the adductor muscles and ramifies in 

 the dorsum at the place of attachment of these muscles. The 

 other nerve (i')i) runs posteriorly a little te the right of thecopu- 

 latory organ. On this course a branch is given off to the salivary 

 gland. At the level of the bifurcation of the aorta the nerve 

 enters a small triangular ganglion (4), situated in the connective 

 tissue close to the reproductive gland. The ganglion gives rise 

 to three nerves. The smallest one of these (5) passes to the 

 reproductive gland. A larger branch (7) takes a posterior and 

 median direction along the posterior artery to enter the liver and 

 the intestine. The largest branch (6) takes a dorsal and anterior 

 direction towards the kidney, but before reaching that organ it 

 bifurcates, both filaments entering the ventral side of the kid- 

 ney. The nerve that follows the posterior artery (7) gives off 

 two very tiny branches to the aorta, but I was not able to follow 

 them on to the ventricle. Nor was I able to trace the nerves 

 that enter the kidney to the musculature of either the ventricle 

 or the auricle, although a branch can be followed to within 2 

 mm. of the base of the auricle. The physiological experiments 

 prove, however, that fibers from the visceral nerve enter the 

 auricle and the ventricle at the base of the auricle. 



The pallio-visceral nervous complex in Ariolimax (\. VII., Fig. 

 1 8) does not differ essentially from that of the slug just described. 

 The left mantle and pallial nerve (2) enters the pallial complex 

 close to the rectum. The visceral nerve (?'#) is given off dorsal 

 and a little to the left on the median protuberance of the gang- 



