1913] Gee: Behavior of Leeches 213 



with the necessary differences that they are much more slowly 

 execvited and no progress forward is made as a result of them. 

 The body is not so flattened as in the swimming movements and 

 sways frequently from side to side. In Glossiphonia staynalis 

 the undulations are necessarily not so pronounced as in Diva, 

 owing to the differences in structure of the body in the two 

 genera. However, the execution of undulatory movements is to 

 be observed as frequently in this species as in the nephelid. 



These movements were observed by Moquin-Tandon (1846). 

 who says in regard to them: "Plusieurs Hirudinees, telles que 

 les sangsues, les Nephclis, la plupart des Glossiphonies, aiment 

 beaueoup a se fixer par la ventouse anale et a se balancer dans 

 I'eau. . . . Les Nephelis par un balancement ondulatoire, met- 

 tent leur peau en contact incessament renouvele avec I'air dissous 

 dans 1 'eau. Les sangsues et les Haemopsis exercent plus rarement 

 les mouvements dont il s 'agit mais ces animaux sont moins exchi- 

 sivement aquatiques que les Nephelis. Les Glossiphonies, qui ne 

 peuvent pas vivre hors de I'eau, nous offrent des especes qui se 

 balancent avec vivaeite, et d'autres qui restent presque constam- 

 ment immobiles ; mais ces dernieres viennent souvent a la surface 

 du liquide oii elles se tiennent le corps moitie dans I'air, moitie 

 dans I'eau." 



As already mentioned, during these movements the body 

 sways from side to side, as if exploring in a limited way the 

 immediately surrounding region of its environment. It was con- 

 jectured that perhaps the movements were connected with the 

 feeding reactions, enabling the leech more readily to locate the 

 food about it. So the effect of the addition of some extract from 

 a couple of macerated snails {Limnea) was observed in order to 

 determine whether the undulations might not be readily evoked 

 in this way. Six small dishes, each containing two specimens of 

 Dina and kept quiet for a couple of hours previous, were used, 

 the last being kept for a control. Though strengths varying 

 from one to ten drops in the separate dishes were used, no re- 

 sponses of the nature of undulatory movements was evoked in 

 any of the dishes, the diffusing juices of the macerated snail 

 serving only to excite the animals to more vigorous locomotor 

 movements. 



