50 COE 



layer is divided into an outer and an inner portion in the region where 

 the glands are situated. The ducts from the glands (p1. xi, fig. i, 

 smg) pass through the muscular layers and basement membrane to 

 open to the exterior among the epithelial cells of the integument. 

 These glands become smaller and more scattered near the region of the 

 nephridial openings, but do not disappear entirely until near the end 

 of the esophagal region. 



Alimentary canal. — The mouth and proboscis open together into 

 the rather long rhynchodaeum. The esophagus is as usual in the genus. 

 A single pair of small intestinal caeca reach forward well toward the 

 brain region. They lie immediately below the esophagus, and near 

 the middle line. Farther back they join a median, broad, unpaired 

 caecum. This has wide, paired, lateral outgrowths which, still farther 

 back, alternate with clusters of reproductive glands. These lateral ap- 

 pendages of the caecum lie mostly above the reproductive glands, as 

 well as alternate with them. Much farther back the esophagus de- 

 creases greatly in size and opens into the intestine by a longitudinal 

 slit in the dorsal wall of the latter. The intestinal pouches are rather 

 deep ; the anus is subterminal. 



Nephridia. — The nephridial canals reach anteriorly nearly to the 

 region of the brain, where there is a single branched longitudinal ves- 

 sel on each side. Throughout the greater part of its length, this main 

 canal lies above the lateral nerve cord, but sometimes lies internal to 

 it or above it. In the anterior third of the esophagal region the main 

 canal becomes very large ; here an efferent duct branches off, passes 

 outside the lateral nerve, and bends downward to open on the exterior 

 of the body on the ventro-lateral aspect. There is but one efferent 

 duct on each side, and the two are sometimes exactly paired. Back of 

 the efferent ducts, the nephridial canals decrease rapidly in size, and 

 disappear far in front of the anterior end of the intestinal region. 



A pair of large blood lacunae lie in the anterior portion of the head 

 as usual. In the brain region they divide into numerous smaller ves- 

 sels (p1. XI, fig. i). The lateral vessels form a broad anastomosis with 

 the dorsal vessel above the anus. 



Nervous system and sense organs. — The dorsal ganglia are closely 

 fused with the ventral. They are without distinct posterior lobes, and 

 sink gradually into the ventral ganglia (p1. xi, fig. i). The cerebral 

 sense organs are well developed. They lie in front of the brain, 

 some distance ventrally from the dorsal ganglia, and communicate with 

 the exterior by a canal which opens ventro-laterally. Each sense 

 organ is lobulated posteriorly and provided with a large nerve {son., 



