CEPHALOPODA. 



57 



to the Pteropods. The morphological relation between these two 

 groups was first thoroughly discussed by R. Leuckart. lie showed 

 that the cephalic cones (tentacles) of Clio correspond to the cephalic 

 arms of Cephalopods, while the median lobe of the foot, represented 

 by the cervical collar, is the equivalent of the funnel. Huxley, 

 however, does not take this view ; he holds that the arms are parts 

 of the propodium and that the funnel, which is formed by the fusion 

 of paired folds, 

 is equivalent to 

 the paired ele- 

 ments of the 

 epipodium 

 which in Ptero- 

 pods form the 

 fins. 



The mantle 

 cavity is placed 

 on the posterior 

 surface of the 

 body, which in 

 the natural po- 

 sition is the 

 under surface. 

 In it are placed 

 on each side 

 one (Dibranchi- 

 ata) or two 

 (Tetrabranchi- 

 ata) gills, the 

 anus, the paired 

 renal openings, 



FIG. 530. Octopus macropus, creeping (after Verany). T, funnel. 



and the genera- 

 tive opening which is sometimes single and sometimes paired. The 

 eyes and olfactory organs are placed at the sides of the head. 

 Anteriorly around the mouth four pairs of fleshy cephalic arms, 



chromolithographies d'apres le vivant." I e Partie. Cephalopodes de la Medi- 

 terranee. Genes, 1847-51. 



H. Miiller, " Ueber das Mannchen von Argonauta argo und die Hecto- 

 cotylen." Zeit.filr n-iss. Zool., 1855. 



Jap. Steenstrup, " Hectocotylus dannelsen hos Octopodsl., etc." K. Dankx. 

 V'ulcnsk. ScWtabs Skrifter, 1856. Uebersetzt im Archivfiir Naturgesoh., 1856. 



Alb. Kolliker, " Eiitwickelungsgesch. der Cephalopoden." Zurich, 1844. 



