1913] Gee: Behavior of Leeches 233 



after havint? escaped from the aquarium Dina will dry to such 

 a state that it is beyond recovery upon being x^laeed in the water. 

 There seems to be no characteristic posture assumed in the drying 

 up of this species. The body is twisted into various shapes as 

 the final result of the desiccation, the most common one having 

 the anterior and posterior tips drawn in towards the center of 

 a semicircular arch formed by the body. During the process 

 of drying the nephelid is often exceedingly active, the contraction 

 of the muscles of the body, affected by the drying, forcing the 

 animal to assume widely different attitudes successively. 



Frequently when removed from the water, Glossiphonia will 

 roll itself up in the "pill bug" fashion, and consequently is able 

 to withstand considerably more exposure to drying influences 

 than Dina. However, the ability to withstand desiccation is not 

 a well developed feature of the repertoire of either of these two 

 genera. 



VI. SPECIAL FEATURES OF BEHAVIOR IN LEECHES 



1. Modifications op Behavior During the Breeding Season 



Unfortunately, among the hundreds of Di)ia microsioma kept 

 under constant observation in aquaria, no egg cocoons or other 

 signs of breeding were observed. The only recorded observations 

 on the breeding behavior of the nephelid leeches that I have been 

 able to find are those of lijima (1882). This worker noted what 

 he construed as abnormal copulation, but which was later inter- 

 preted by Whitman (1891) as hypodermic impregnation through 

 the agency of spermatophores. Quoting from Whitman: "Al- 

 though it is well known that spermatophores are of general 

 occurrence among the invertebrates, and even among many verte- 

 brates, the assertion that, as a perfectly regular and normal 

 affair, in animals as highly organized as the leeches, they repre- 

 sent an injecting apparatus by means of which the .spermatic 

 elements of one individual are forced through the body wall of 

 another at any point whatsoever, may appear almost incredible, 

 even when supported by direct observation many times repeated 



