310 



EVENINGS AT THE MICEOSCOPE. 



Here it is. Theie is no protrusile proboscis, but the 

 throat is spacious, and capable of being everted to a 

 slio;ht deforce. The front border of the mouth is en- 

 larged so as to form a sort of npper lip, and this com- 

 bines "with the wrinkled muscular margin of the lower 

 and lateral portions to form the sucker. With the dis- 

 secting scissors I slit down the ventral margin of the 



sucker, exposing the whole 

 throat. Then, the edges 

 being folded back, we see 

 implanted in the walls on 

 the dorsal reo;ion of the 

 cavity three white emi- 

 nences of a cartillao^inous 

 texture, which rise to a 

 sharp crescentic edge; thej 



THROAT OF LEECn LAID OPEN. 



form a triangular, or rather a triradiate figure. 



Now, if you recollect, this is the figure of the cut 

 made in the flesh wherever a Leech has sucked, as it is 

 of the scar whicli remains after the wound has healed. 

 For these three little eminences are the implements Avith 

 which the animal, impelled by its blood-sucking in- 

 stincts, effects its purpose. But to nnderstand the ac- 

 tion more perfectly, wo must use higher powers. 



I dissect out of the flesh, then, one of the white 

 points, say the middle one, and laying it in water in 

 the comprcssorium, flatten the drop, but use no more 

 pressure than just enough for that. jSTow I apply a 

 power of 150 diameters, and we will look at it in suc- 

 cession. Yon have nnder your eye a sub-j>ellueid mass, 

 of an irregular oval figure, and of fibrous texture, one 

 side of whicli is thinned away apparently to a keen 



edge of a somewhat semi-circular outline. 



But along 



