NEMERTEANS 



249 



B 



Form and colour of spirit specimen. The length is 2-8 cm., the greatest breadth 0-35 

 cm. The body is round in section anteriorly, flattened from above down posteriorly. 

 The head is small and pointed 

 and is separated from the m 

 body by a shallow circular 

 depression. The mouth is 

 mid-ventral — a small slit with 

 definite lips — situated in the 

 depression and on each side 

 are small vertical furrows 

 (Fig. 21 A). 



Anatomy. Frontal organs 

 are present but head glands 

 appear to be completely miss- 

 ing. The proboscis pore is a 

 narrow slit placed ventrally 

 not far from the tip of the 

 head. Before its appearance 



in transverse section the vas- Fig 2I Parapolia grytvikenensis, n.sp. A, sketch of preserved 

 cular lacunae are present. specimen; m, mouth; eg, cephalic slit. B, outline of the head (from 



The body layers can be seen above) from a graphic reconstruction showing the brain, cerebral 

 in Fig. 22. The glands in the organs, and the position of the mouth (m). 

 cutis are few and incon- 

 spicuous. The epithelium is 

 thin. The slender proboscis 

 has definitely the Lineid ar- 

 rangement of muscle layers. 



The brain is small and /r^^v ',, ^^S^^^^.?- ^■'.^vd?' 



ill-defined, the fibrous part 

 mingling with the muscles. 

 The cerebral organs are also 

 small. They lie close above 

 the ventral ganglia where these 

 are passing laterally into the 

 lateral nerves. I could trace no 

 direct connection between the '*/ *fc> 



cerebral organs and the dorsal pig. 22. Parapolia grytvikenensis, n.sp. Part of a transverse section 

 ganglia. The organs open to of the head at the posterior end of the brain, cc, cerebral canal; 

 the exterior by fine lateral d S> dorsal ganglion ;p, proboscis; vg, ventral ganglion. 



canals (Fig. 21 B). 



The anterior end of the mouth follows directly the disappearance of the cerebral 

 organs from transverse sections. There are no eyes. 



5-2 



