i6 4 



THE NEMERTINJ 



i 



Fio. II. 



Deeper dissection of the anterior end of 

 Cerebra'ulus, after removal of the proboscis, and 

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

 lateral nerve trunks are omitted, a, rhyncho- 

 stoine; b, rhynchodaeum ; e, dorsal ganglion, 

 or superior lobe of the brain, wih dorsal com- 

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

 i l:ii-uin ; K; intestine ; A-', caeca ; 7, excretory pore, 

 leading into the excretory duct, and thence to 

 the branching canal, alongside the lateral blood- 

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

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

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

 terior anastomoses. 



Fio. III. 



Plan of the vascular system of Cerebra- 

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

 o, transverse vessels ; ;>, lateral vessels ; 

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

 parastomodaeal sinus and network ; </', 

 the median vessel giving origin to these ; 

 5, preoral anastomosis in region of brain ; 

 t, supra-anal anastomosis ; m, mouth. 



