I4O A. J. CARLSON. 



(7) which pass towards the base of the auricle and perhaps into 

 the venous sinuses between the auricle and the gill. In 

 the largest specimens one or two of these branches can be traced 

 to the base of the gill. This nerve is probably homologous to 

 the nerve in Aplysia and Bulla which runs in the ventral wall of 

 the pericardial cavity and supplies the heart and the renal organ. 

 Parallel to this nerve runs an extremely small branch (6), some- 

 times given off from the ganglion, sometimes from the auricular 

 nerve itself. The branch enters the pericardium. And lastly, 

 the ganglion gives off a comparatively large nerve which takes a 

 posterior and median direction and enters the genital glands (4). 



6. The Nudibranclis. - - The innervation of the viscera in Doris 

 tuberculata has been described in great detail by Hancock and 

 Embleton (1852). Four visceral nerves take their origin from the 

 right and ventral side of the supracesophageal ganglionic mass. 

 One of these nerves sends branches to the renal organ, the gill, 

 the vesicle ventral to the pericardial cavity (believed by these 

 investigators to be a " portal heart "), and to two ganglia situated 

 " on the apex of the ventricle." Besides these two ganglia on 

 the ventricle they describe a great number of small ganglia on 

 the peripheral course of the visceral nerves. Pelseneer (1893) 

 designates two small nerves from the abdominal ganglia in the 

 two Dorididse Polycera and Goniodoris as " reno-cardiac nerves," 

 but he does not follow them to their entrance of these organs. 



My own work done on the three Dorididae, Montereina nobilis, 

 Trioplia carpcntcri and Trioplia grandis. Montereina is the largest 

 nudibranch at my disposal, and for that reason best adapted for 

 working out the cardie innervation and for isolating the cardiac 

 nerves for the physiological experiments. In this mollusc (PI. 

 VI., Fig. 14) the oesophageal chain of ganglia as well as the greater 

 part of the visceral ganglia are fused into one supracesophageal 

 ganglionic mass, the more primitive arrangement of the ganglia 

 being indicated by the presence of the stout commissure which 

 passes under the oesophagus and connects both sides of the 

 ganglion. From the right and ventral side of this composite 

 ganglion near the origin of the cesophageal commissure a nerve 

 (vti) is given off, which takes a posterior direction ventral to the 

 two posterior nerves to the mantle. On reaching a branch of 



