NEMERTEANS 



133 



tegument. The few glands about the rhynchodseum do not extend 

 back as far as the brain. 



Integument of body remarkably thick and closely packed with 

 glands. In the intestinal region the glands are vastly more abundant 

 on the dorsal than on the ventral surface. It is in this layer that the 

 pigment wliich gives the body its characteristic transverse and longi- 

 tudinal dark markings is situated. Unless stained too deeply the posi- 

 tion of the markings is distinctly seen in each transverse section. 



Proboscis. — Of small size, yellowish or ochre in color. Muscular 

 and epithelial layers as in other species of genus ; fibrous layer, situated 

 externally, unusually strong ; proboscis nerves, beneath internal epithe- 



yc 



,tc-m, 



Fig. 17. C.frenata. Transverse section of body in region of 

 nephridiopores. X ~S' 



Hum, remarkably large and conspicuous. Proboscis sheath well de- 

 veloped. In the exact region of the efferent nephridial ducts the cavity 

 of the proboscis sheath becomes divided. A very small chamber, 

 situated dorsally (text-fig. 17, re), passes backward for some distance, 

 and in this the retractor muscle of the proboscis extends to the posterior 

 attachment; while the ventral chamber (re'), which is very much the 

 larger, passes backward but for a short distance where it ends in a broad, 

 blind sac. The retractor muscle is attached to the dorsal wall of the 

 smaller dorsal chamber a little distance back in the intestinal region, and 



