72 



THE APODID^ 



PART I 



crossing of the nerves must take place. Our own 

 examination of the nervous system quite confirmed 

 this, as shown in Figs. 19, 20, and 21. These figures 



Fig. 19. — Diagram to show the derivation of the central nervous system of Apus from 

 that of a bent AnneHd as in Fig. i8 ; drawn on the assumption that the nerves 

 of the first antennae of the original Annelid branched from the first ventral 

 ganglion, i, 2, 3, 4, 5, ganglia of the ist, 2nd, 3rd, 4th, and 5th segments. /', 

 brain of Annelid ; /3, of Apus ; cei, oesophageal commissures of Annelid ; ce2, <^3) 

 the two oesophageal commissures of Apus derived from cvi ; rtj, a2, nerves to the 

 1st and 2nd antenna; of the Annelid ; ax, a2, ditto of Apus ; ci, e-2, nerves to the 

 eyes of the Annelid ; 171, 172) ditto to those of Apus. 



should be compared with Figs, i and 2, which show 

 the positions of the antennae. 



This position of the first antennal nerve tells us, 

 however, nothing definite as to the position of the 



