THE NEMERTINI 



s-t- 



FIG. II. 



Deeper dissection of the anterior end of 

 Cerebratulus, after removal of the proboscis, and 

 of the greater part of the dorsal blood-vessel. The 

 lateral nerve trunks are omitted, a, rhyncho- 

 stome ; &, rhynchodaeum ; e, dorsal ganglion, 

 or superior lobe of the brain, with dorsal com- 

 missure intact ; h, cerebral organ ; j, stomo- 

 daeum ; k, intestine ; k', caeca ; I, excretory pore, 

 leading into the excretory duct, and thence to 

 the. branching canal, alongside the lateral blood- 

 vessel ; m, gonad (perigonadial coelom) ; m', 

 genital pore ; n, dorsal blood - vessel ; o, trans- 

 verse vessel ; p, lateral blood-vessel ; r, s, an- 

 terior anastomoses. 



t- -\- 



FIG. III. 



Plan of the vascular system of Cerebra- 

 tulus, from above, n, dorsal blood-vessel ; 

 o, transverse vessels ; p, lateral vessels ; 

 p (above), anterior, apical anastomosis ; q, 

 parastomodaeal sinus and network ; q', 

 the median vessel giving origin to these ; 

 s, preoral anastomosis in region of brain ; 

 t, supra-anal anastomosis ; m, mouth. 



