20G University of California Publications in Zoology [Vol. 11 



Biedermann (1910) in Winterstein 's Vergleichende Physiol- 

 ogie discusses rather fully the literature bearing on the food- 

 taking and digestive processes in the Hirudinea. 



Moltschanov (1911) records nemiclepsis marginata, H. tessu- 

 lata, Glossiphonia heterodita, and Gl. bioculafa as carrying their 

 eggs attached to the ventral surface of the body. Upon emerging 

 from the egg, the young leeches attach themselves by their suckers 

 to much the same ventral portion of the parent as was occupied 

 by the eggs and remain in this position until about one-third 

 grown. The epithelial cells are specialh' modified so as to pro- 

 vide the easy attachment of the suckers, and it is suggested that 

 the secretion of these cells furnishes food material for the young 

 leeches. 



Bolsius (1911) confirms in large part the observations of 

 Moltschanov, and places Glossiphonia sexoculata among the 

 species which carrj* their young. This species he records as 

 carrying about fifty young per individual ; while in Hemiclepsis 

 marginata he states that he has seen as many as ninety-two young 

 inflicting themselves upon a single adult. 



Naehtrieb, Moore, and Hemingway (1912) in their discussion 

 of the leeches of Minnesota give much interesting material on 

 the structure and classification of leeches, with a brief treatment 

 of the natural history of these animals. Moore includes in his 

 classification observations on the food of Glossiphonia stagnalis 

 and Hemiclepsis occidentalis. An excellent description of this 

 latter form is also included. 



III. DESCRIPTION OP MATERIAL 

 The experiments described in the following pages were eon- 

 fined exclusively to three species of leeches, each representative 

 of a difierent genus. The great bulk of the results was secured 

 from the nephelid Dina microstoma Moore and from Glossiphonia 

 stagnalis Linnaeus. Specimens of Hemiclepsis occidentalis Ver- 

 rill were more difficult to secure and for that reason form the 

 basis for relatively few observations. 



Dina microstoma is fully described by Moore (1901) in his 

 paper on "The Hirudinea of Illinois." The species is generally 

 slender, and approximately 42 mm. in length. The mouth is 



