202 bulletin: museum of comparative zoology. 



head is broader than neck. Cephalic furrows moderately long, very 

 deep, with thin margins; when anterior margin of head is some- 

 what contracted, cephalic farrows meet in front above proboscis 

 pore. Caudal cirrus small but conspicuous, and not as readily 

 broken off as in many related species. Ocelli wanting. 



Body remarkably fragile even when sexual products are very 

 immature, so that the living worms can seldom be handled without 

 the body becoming ruptured. 



Length 10-1.5 cm. or more ; width 4-5 mm. in intestinal region. 



Color. — Dull or rosy flesh colored or cream colored anteriorly; 

 head paler and more translucent, except brain, which is dull red or 

 wine color. Lateral margins in intestinal region thin, pale gray, 

 and bordered internally by a conspicuous reddish line indicating 

 position of lateral nerves. On dorsal surface proboscis sheath is 

 indicated by a more reddish color. 



Intestinal region less rosy, more nearly cream colored or of a 

 pale buff color. Proboscis pale buff or grajdsh. 



When preserved in formalin, color completely disappears in a day 

 or two, except the darker tint of the brain which is retained for 

 some days longer. 



Proboscis of moderate proportions. Internal longitudinal mus- 

 cular layer wanting, the basement layer of epithelium resting 

 directly u})on the nerve plexus. Muscular crosses between cir- 

 cular muscular layer and the very thin layer of circular muscles 

 beneath the outer, flattened epithelium very conspicuous on both 

 dorsal and ventral sides. 



Cephalic glands well developed, extending through all parts of 

 the tissues of head in front of brain. Cutis glands limited to oiUer 

 portion of outer longitudinal muscular layer. 



Alimentary canal. — Esophagus clearly exhibits the usual division 

 into two chambers, esophagus proper and stomach, lined with differ- 

 entiated epithelium. 



Blood and nephridial systems. — A large median blood lacuna 

 near tip of snout extends backwards for some distance toward brain 

 before dividing into the two usual lateral lacunae. Extensive 

 esophageal lacunae surround anterior portions of esophagus on 

 three sides. Somewhat behind the nephridial region these are 

 gathered into the lateral vessels which are found in the stomach 

 rei3"ion, and which are much smaller and have stronger walls than 



