220 University of California Pnhlications in Zoology [Vol-. 11 



activity, or positiveness of response, when made at the anterior 

 end, or when the diffusing food juices had come in contact with 

 the mouth region of the body. This is very closely in accord 

 with what has been found by Whitman in the blood-leech, and 

 from such behavior one is inclined to conclude that cells adapted 

 to taste functions are present principally in the mouth region 

 of the leech. This view is further strengthened by the fact that 

 diffusing food juices have practically no effect upon decapitated 

 specimens. 



The family to which Dvna microstoma belongs is characterized 

 as "non-parasitic, carnivorous, and without denticulate jaws." 

 In Glossiphonia stagnMs the position of the mouth, according 

 to Castle (1900), is in the third somite, and leads dorsally into 

 the pharyngeal sac, which continues backwards, ending in the 

 thirteenth somite. A short oesophagvis, extending the length of 

 only one somite, connects this with the crop. 



In the feeding of Dina microstoma, the posterior sucker is 

 attached either to the bottom of the dish or to the surface of the 

 material on which the animal is feeding, and the anterior sucker 

 is applied to the food. The feeding seems to be a combination 

 of sucking and tearing; the mouth is applied for many seconds 

 continuously and then suddenly the head may be pulled loose 

 from the mass of food, and later reapplied. The animal seems 

 to have the power as described by Moquin-Tandon of removing 

 often considerable pieces of food and swallowing them entire. 

 The appearance of a worm or a piece of snail after the animal 

 has fed to satiety is another very good piece of evidence to 

 substantiate such a view, since there is little or none of it left. 



Whitman (1898) says: "Many species of Clepsine require 

 but one full meal a year, and as they seldom live more than two 

 or three years the number of meals is very limited. ' ' Starvation 

 experiments conducted on Dina microstoma show that after more 

 than six months of fasting eight specimens of this species still 

 retain considerable vigor. There is evident in these specimens, 

 however, a marked reduction in size. 



When a dish containing a number of active Glossiphonia is 

 provided with a couple of earthworms, only a few minutes suffice 

 for the most of the leeches to locate the prey. Of certain species 



