77 



connective to the pedal ganclion (r) ol' the same side. At 

 t'.ie side of tlie cerebral are the pleural ranprlia , distinct- 

 ly separated from them, and sending connectives posterior- 

 l3' to tlie visceral E^an^lia. I think thero in alno a pleu- 

 ro-pedal connective at this stage, out this I am not able 

 to state positively. The pedal ganglia at this stage are 

 as co^1l^letely fused as in the adult, o j just poste- 

 rior to the beginning of the oesophagus (fig. 24) . Lying 

 immediately in front of the j^osterior adductor muscle 

 (figs, 2,24, 26), the visceral ganglia form a long cylin- 

 der enlarged at both ends. The commissure here contains 

 ganglion cells, T'-^ ■^■o sides rapidly become more close- 

 ly ftised and in the early stage represented in fig. 4, 

 the concentration is almost as great as in the adult. 

 Each visceral ganglion of the larva gives off a respira- 

 tory nei've which bears a respiratory ganglion still far 

 apart from the visceral. TiVhile tlie visceral ganglia are 

 becoming more closely fused, the commissures between the 

 cerebral aad pleuial ganglia are becoming obliterated. These 

 ganglia persist as seperate masses in the young "Ship- 

 v.'orm" of three or four days (fig. 4), but soon afterwards 

 fuse completely, though sections of latter stages still 



