CERATA OF DENDRONOTUS. 349 



but does not figure the basal portions. As the result of 

 our investigations, both by dissections and by means of 

 thin serial sections we ventured to express our disbelief 

 in the existence of these hepatic caeca in the cerata ; we 

 described and figured what we considered to be the 

 correct structure of the cerata, and showed that although 

 the liver is prolonged into short processes which run in 

 the direction of some of the cerata, there is no hepatic 

 tissue to be found in the cerata themselves.* Last year 

 Dr. Paul Pelseneer, in his " Recherches sur divers 

 Opisthobranches,"! in a paragraph on the digestive system 

 of Dendronotus briefly refers to our conclusions with 

 regard to the structure of the cerata. He says " D'apres 

 Herdman, le foie ne ramiferait pas dans les deux premieres 

 pairs d'appendices dorsaux ; les individus etudies m'ont 

 presente ces appendices pareils aux autres ; le foie est 

 done repandu dans toutes les saillies dorsales et dans le 

 corps, ou il occape la meme position que dans Tritonia." 



It appears from this that Pelseneer has somewhat mis- 

 understood the results we then arrived at, for we not only 

 stated that the liver did not ramify into the first two 

 pairs of cerata, but also that it did not ramify into any. 

 Prof. Herdman at once suggested, as part of my work 

 while holding the University Scholarship, that I should 

 carefully revise all our previous investigations, examine 

 afresh our old preparations, and make what new ones I 

 should find necessary in order to settle definitely this 

 vexed question of the hepatic processes and dorsal cerata 

 of Dendronotus. 



This I proceeded to do. I went carefully over the whole 



*Zoc. cit., p. 230. 



tExtrait du tome LIII. des 3Iemoires couronnes et Mcmoires clcs savantes 

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

 Belgique, 1894. 



