PLATE XII. 



Fig. i. Paranemertes pallida. Transverse section through nephridial region. 

 In this case the single pair of efferent nephridial ducts (nep) was so 

 symmetrically placed that both were cut in a single section. The very 

 small size of the proboscis (ps) in the large proboscis sheath (fis/i) is 

 remarkable. The intestinal caecum (ic) shows lateral diverticula above 

 the lateral nerve cords. (X *8). 



2. Amphiporus bimaculatus. Transverse section of proboscis. The 16 

 proboscis nerves (p) are very sharply defined. The cylindrical plexus 

 (tip) of nerve fibers and connective tissue serves to connect the nerves, 

 and divides the thick longitudinal muscular band into an inner {pint) 

 and an outer (pirn 1 ) layer. The inner longitudinal muscular layer, 

 found in most related species, is wanting the basement layer (btn) of 

 the internal epithelium (pep) lying immediately beneath the circular 

 muscular layer. ( X 66) . 



3. Etnplectonema burgeri. Transverse section through body, showing 

 manner in which the esophagus (e) opens into dorsal wall of intestine 

 (in). This section also shows the genital pouches (gp) lying both 

 above and below the intestinal lobes, and indicating that they open 

 respectively on the dorsal and ventral surfaces of the body. Of the 

 submuscular glands (smg), which extend throughout the esophagal re- 

 gion in great abundance but a few remain as far back as the position of 

 the section figured. (X20). 



(108) 



