CEEATA OF DENDEONOTUS. 233 



Plate XV. 



Fig. 1. Diagrammatic scheme of the anterior part of the 

 dorsal and lateral epipodial nerves of Dendronot us 

 arborescens, showing in lateral view their origin 

 from the ganglia, their branches, and the anas- 

 tomosis between a and c. 



Fig. 2. Drawn from a T.S. section (the 283rd in the serial 

 series) through the body of Bendronotus just 

 anterior to the point of origin of the branch from 

 the dorsal pedal nerve (in the plane marked by 

 the dotted line 2 in the diagrammatic scheme, 

 fig. 1). The relative position of the nerve 

 a (epipodial nerve) arising from the pleural 

 ganglion, of the nerve b (dorsal pedal nerve) 

 arising from the pedal ganglion and of the 

 oesophagus ce is seen. 



Fig. 3. Drawn from the next section behind fig. 2 (in the 

 plane of the dotted line 3 in fig. 1). Here the 

 branch c. is beginning, and the perineurium is 

 seen partly cutting it off from b (dorsal pedal 

 nerve) . 



Fig. 4. Drawn from the next section posterior to fig. 3 (in 

 the plane of the dotted line 4 in fig. 1). The 

 branch c is now completely invested in its distinct 

 sheath, and its fibres are completely separated 

 from those of b (dorsal pedal nerve). 



Fig. 5. Drawn from the fourth section posterior to fig. 4 

 (in the plane of the dotted line 5 in fig. 1). The 

 branch c is now seen some distance from the 

 pedal nerve b, and close to the epipodial nerve a. 



Fig. 6. Drawn from the succeeding section to fig. 5 (in the 

 plane of the dotted line 6 in fig. 1) . The epipodial 

 nerve a is here seen to have a distinct constriction, 

 with a part d being separated off. 



