CEEATA OF DENDKONOTUS. 355 



sure indication of homology, and we put forward the 

 suggestion that possibly the innervation has undergone 

 modification so that, while these ceratal outgrowths may 

 be truly epipodial, commencing as pedal structures, 

 supplied with nerves from the pedal ganglia, they may 

 have secondarily acquired in the different types mentioned, 

 as the result of changes in form, position and relation to 

 other organs, the various conditions of innervation which 

 we described. This, however, was merely a suggestion, 

 and requires further elucidation by the examination of the 

 nerve supply in other species, which as soon as I can 

 obtain the necessary material I hope to undertake. 



The immediate object of this communication is with 

 regard to the nerve supply to the cerata of Dendronotus 

 arborescens. Since the previous paper in the Q. J. M. S., 

 Prof. Pelseneer in his " Kecherches sur divers Opistho- 

 branchs "* refers to the conclusions we arrived at in 

 regard to this point. In Dendronotus we described and 

 figured! an anastomosis of a branch from the pedal nerve 

 with the pleural element of at least a part of the epipodial 

 nerve. We found from the examination of a complete 

 series of sections of an entire Bendronotiis arranged 

 serially, that a nerve, arising from the pleural ganglia 

 (epipodial nerve), runs backwards for a short distance and 

 then divides into a dorsal branch (dorsal epipodial nerve), 

 and a ventral branch (lateral epipodial nerve) ; also that a 

 nerve arising from the dorsal aspect of the pedal ganglion 

 (dorsal pedal nerve) runs backward a short distance, and 

 then divides into two. The upper branch anastomoses 

 with the lateral epipodial nerve just after it has given rise 



* Extrait du tome LIII. des Memoires courvnnes et Metnoires des savantes 

 etranger. L'Academie royale des sciences, des lettres et des beaux arts de 

 Belgique, 1894. 



■\Loc. cit., PL XXXIV., fig. 27. 



