PLATE XII. 



Fig. I. Para7iemertes 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 {fsh) is 

 remarkable. The intestinal caecum (/c) shows lateral diverticula above 

 the lateral nerve cords. (X iS). 



2. Amfhiporus bunaculatus. Transverse section of proboscis. The i6 

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

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

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

 and an outer {pint') layer. The inner longitudinal muscular layer, 

 found in most related species, is wanting — the basement layer {bm) of 

 the internal epithelium {pep) lying immediately beneath the circular 

 muscular layer. ( X 66) . 



3. Emplectonema burger i. Transverse section through body, showing 

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

 («'«). 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). 



(io8) 



