186 



ONYCHOPHORA. 



a method of feeding which also occurs in the embryos of P. capensis ; 

 in addition to this there is a kind of endosmotic inception of 

 nutritive fluid. 



Interpretation of the cephalic appendages of Peripatus. The 

 nature of the two posterior pairs of cephalic appendages of Peripatus 

 cannot be doubted. They correspond to the limbs of the trunk, 

 and might without further question be assumed to be limbs which, 

 when two (primary) trunk -segments were fused with the head, 

 were transformed into jaws and oral papillae. This is not the 

 case with the antennae, which are distinguished from the limbs of 

 the trunk by their dorsal and pre-oral position. In this respect 

 they entirely agree with the antennae of the Myriopoda and the 



Insecta, witli which we 

 a consider them homo- 



logous. The antennae 

 of Peripatus seem un- 

 doubtedly homologous 

 with those of all the 

 other Tracheata, but 

 not with those of the 

 Annelida. The an- 

 tennae, not only of 

 Peripatus, but of the 

 Myriopoda and In- 

 secta, have been com- 

 pared with regard to 

 their position to the 

 cephalic tentacles of 

 the Annelida, which 

 are found (pre-orally) 

 in the cephalic seg- 

 ment, occupying the same position with relation to the neural plate 

 as do the antennae of the higher forms with relation to the brain. 

 The manner in which the antennae of Peripatus originate, however, 

 seems to us to tell against such a comparison. The antennae, both 

 as rudiments and when developing, show great agreement with the 

 trunk-limbs (Figs. 91-94), a fact which is strikingly evident in 

 the figures given by Sedgwick and v. Kennel. Like the limbs, 

 they are externally ringed, and a process of the primitive segment 

 runs into each of them, so that they too are hollow cones. Indeed, 

 a canal is said to run from the primitive segment of the antenna 



Fig. 95. — Head of P. Edwardsii, ventral aspect (after 

 Sedgwick, from Lang's Text-book of Comp. Anat.). a, 

 antenna (the greater part of which is removed) ; op, oral 

 papilla. In the buccal cavity are the double jaws. The 

 cavity itself is surrounded by the folds cut up into 

 papillae. 



