No. 3.] SPERMATOPHORES. 



379 



Clcpsinc parasitica, as described by Say ^ and Verrill,^ agrees 

 in certain features closely with the dark species, and Verrill's 

 C. papillifcra var. carinata viay be identical with the light 

 species. The descriptions, however, do not point out any char- 

 acters which can be relied upon for identification. 



The dark specimens, to be described in the following paper 

 under the name C. plana, were ready to copulate whenever they 

 met ; but they always avoided the light species, which may be 

 provisionally designated as C. carinata. The latter showed no 

 disposition to copulate until early the following spring. They 

 remained quiet during the winter ; but on being started up in 

 May, they began to deposit sperm-cases. 



The observations which follow are confined m.ainly to C. 

 plana. Two of this species bore young still stuffed with yolk, 

 and another had eggs in its ovaries that were nearly mature. 



When I first placed these Clepsines in a dish together, I 

 noticed several long white bodies attached by one end to the 

 dorsal surface of one or two individuals. I pulled them off for 

 examination, thinking that they were parasites of some kind. 

 Putting them under the microscope, I saw, to my great surprise, 

 a stream of spermatozoa slowly issuing from the end that had 

 been detached. At first I could hardly believe that these sperm- 

 cases belonged to the leech, never having detected the animal 

 in the act of depositing them, and not suspecting that they 

 could discharge their contents through the skin. My curiosity 

 having been thus aroused, 1 watched the leeches more closely, 

 and soon had an opportunity to see the whole operation. The 

 leeches were moving about as they usually do when first cap- 

 tured, before becoming wonted to new quarters. One indi- 

 vidual, coming in contact with another, fixed itself by its oral 

 sucker to some convenient point, and then, while pressing its 

 protruded male pore against the back of its fellow, planted a 

 fresh sperm-case. During the operation, which lasted only a 

 few seconds, the body in the region of the genital pores was 

 more or less constricted, somewhat as it is in the act of forming 

 an egg-cocoon. The constriction seemed to be the expression 



^ Thomas Say : Major Long's Expedition to the Source of St. Peter's River, etc., 

 in 182J. Vol. II, Appendix, p. 14. Keating's Compilation, London, 1825. 



2 A. E. Verrill : Synopsis of North-American Fresh-water Leeches. Professor 

 Baird's Report for 1872-73. 



