80 Journal of Entomology and Zoology 



denticular pouch, serxing the complicated musculature of the four 

 pairs of maxilla?. 



The inner pair of \isceral nerves form the superpharyngeal ner- 

 vous system. Near where they branch off from the outer pair they 

 partly anastomose, interchanging a few fibers, but with no attendant 

 ganglionic structure. The anastomosis continues for a distance of 

 .16 mm. and then the nerves separate, assuming a diameter of .02 

 mm. and run parallel about 2 mm. apart for a distance of 1.3 mm. 

 As they do this they bend dorsally so that they are deeply embedded 

 in the upper wall of the denticular pouch and are quite dorsad of the 

 maxillary musculature. This brings them to where the intestine 

 folds off from the dorsal side of the denticular pouch. The nerves 

 bend still more dorsad and become embedded in the intestinal epi- 

 thelium. Here they become enlarged by ganglion cells and separat- 

 ing (Fig. 4; p), go around the mouth of the intestine proper and 

 come together in the ventral wall of this structure. Just before their 

 second anastomosis they send off two branches into the lateral and 

 dorsal walls of the intestine. These nerves and the one into which 

 the main pair fuses extend back along the intestinal wall for a short 

 distance. 



An interesting observation was made on the muscle which acts 

 on the mandibles. It is a long spindle-shaped muscle reaching from 

 the back of the pharynx to the mandibles. These bifurcate black 

 chitinous plates are in apposition to the slit (Fig. 4; 6), whose walls 

 are armed with the maxilla? and form the denticular pouch. The 

 mandibles are bound to the walls of this slit by small muscles used 

 in prehension. Now the members of this group that has the denti- 

 cular pouch do not completely evert their pharynx in the act of pre- 

 hension. They merely, from what observations I have been able 

 to make on the Eunicichc and on this form, push out the mandibles 

 and the forceps jaw of the maxillae. There is no proboscoideal 

 musculature, such as is found in Phyllodoce, Glycera and Nereis, 

 which functions from the inside and by contracting, turns the pro- 

 boscis inside out. To take the place of the muscles which evert the 

 proboscis by contracting and pulling it out we have in this form a 

 muscle which, acting on the mandible forces this and the forceps 

 teeth of the maxilla- out and does so, paradoxical as it may seem by 



