56 PLATYHELMINTHES. 



2. The straight alimentary canal. The diverticula of the 

 intestine and the terminal anus. 



3. The enormous proboscis, consisting of a large anterior 

 eversible portion, and a smaller posterior portion that is not 

 eversible. When the proboscis is retracted it is bent upon 

 itself. Stylets are present in the eversible portion, near its 

 inner end. Can you determine how the proboscis is protruded 

 and retracted? Does the proboscis have anything to do with 

 the digestive system? 



4. Beneath the posterior eye-spots are the cerebral ganglia, 

 from which lateral nerve cords extend posteriorly. 



5. If the specimen happens to contain eggs, they will lie 

 between the diverticula of the intestine. They are compara- 

 tively very large. 



Coe: Development of the Pilidium of Certain Nemerteans. Trans. Conn. 



Acad., 10, 1899. 

 : On the Anatomy of a Species of Nemertean (Cerebratulus lacteus). 



Trans. Conn. Acad., 10, 1890. 

 Verrill: The Marine Nemerteans of New England and Adjacent Waters. 



Trans. Conn. Acad. Sci., 8, 1892. 

 C. B. Wilson: Habits and Early Development of Cerebratulus lacteus. 



Quart. Jour. Mic. Sci., 43, 1900. 



