Mr. A. Hancock on the Anatomy of Antiopa Spinolse. 33 



pletes the great oesophageal collar. Another nervous trunk (i), 

 but very inferior in size, passes below the oesophagus, and has its 

 extremities attached, at either side, to the under surface of the 

 ganglions near to the point where the pedial are united to the 

 cerebroid and branchial. This is the middle or slender collar, 

 and, as in Eolis, it gives off on the right side a nerve, the tenth, 

 which, passing to the generative organs, is I believe united to a 

 ganglion (PI. III. fig. 6 /) which lies on the sheath of the penis. 

 Of this, however, there may be some doubt, as I was unable to 

 verify the observation from the want of specimens. Several 

 nervous twigs radiate from this ganglion, representing pretty 

 accurately the principal parts of the nervous plexus on the same 

 organ in Doris, and which has been described, as a portion of 

 the sympathetic system, by Dr. Embleton and myself in the 

 communication before alluded to. 



This collar, its nerves, and the ganglion situated on the sheath 

 of the penis have escaped the notice of M. Blanchard, who points 

 out a branch from a small ganglion, which he calls " branchio- 

 cardiaque" in connexion with the right branchial nerve, the 

 " cervico-cardiaque " of this naturalist, as that which supplies 

 the reproductive organs. I have not observed this ganglion and 

 its branch. The eleventh or last pair of nerves, from the supra- 

 cesophageal ganglions, come out of the posterior margin of the 

 branchial, and pass to the dorsal skin, one on each side, and ap- 

 parently supply the papillae ; these are the branchial nerves. 



The two pairs of infra-cesophageal ganglions rest upon the 

 upper surface of the buccal mass below the gullet, and are con- 

 nected, as before stated, to the supra- oesophageal by a wide, 

 slender commissure. The buccal ganglions (fig. 5 e, e) are well 

 developed, though very much smaller than the principal cerebral ; 

 they are elliptical, and are connected across the median line by 

 a commissure much longer than usual ; the commissure from the 

 supra-oesophageal being attached to their outer margin. The 

 twelfth and thirteenth pairs of nerves come from these ganglions ; 

 the former issue from their outer margin in connexion with the 

 commissure, and pass into the buccal mass ; these are the buccal 

 nerves ; the latter come from the posterior margin and dip im- 

 mediately into the buccal mass behind, and are the same which 

 in Doris supply the tongue. 



The gastro- oesophageal ganglions (/,/), though of sufficient 

 magnitude to be readily distinguished, are much inferior in size 

 to the buccal, to which they are united in front by a longish 

 pedicle. The fourteenth, fifteenth and sixteenth pairs of nerves 

 belong to these ganglions ; the two former are applied to the upper 

 portion of the gullet, one probably going to supply some minute 

 salivary gland at present undiscovered. The nerves of the 



Ann. § Mag. N. Hist. Ser. 2. Vol. viii. 3 



