i8 THE LEECHES OF MINNESOTA 



Stomach or Crop. 



In the true bloodsuckers this region has from two to fourteen 

 or more lateral diverticula or pouches technically cald gastric ceca. 

 As a rule there is one pair of these ceca to a somite in the region of 

 the stomach but in some cases there are two pairs to a somite. 

 They are side pockets which serve as reservoirs for the ingested 

 blood. When they are full the leech may leave the host and seek 

 some secluded place where the digestion of the bountiful meal may 

 be continued in peace. The blood does not clot in this region owing 

 to the addition of the secretion from the glands noted above. When 

 all the blood has been digested the leech will actively seek a host 

 for a new supply. The adults of some species may store enough 

 blood in this region to last for several months. The medicinal 

 leech has been known to make one meal last for more than nine 

 months. Generally there are no digestiv or gastric ceca in the leeches 

 which do not suck blood. In this group the digestiv tract is a straight 

 tube markt into the several regions by differences in size and general 

 structure. The stomach or crop opens into a narrower portion cald 

 the 



Intestin 



In the true bloodsuckers this also may have several pairs of 

 lateral diverticula, cald intestinal ceca. When the blood enters this 

 region of the digestiv tract it becomes rapidly changd in color and 

 composition. This indicates that activ digestion takes place in this 

 region. A short terminal portion of the intestin is sometimes so 

 modified that it can be recognizd as a distinct region. When 

 recognizable it is cald the rectum. The intestin or rectum opens 

 to the exterior thru a small inconspicuous opening cald the 



Anus. 



The anus is on the mid-dorsal line usually on or near the 

 boundary between the body and the posterior sucker. 



The general anatomical features briefly noted above are repre- 

 sented in figure 4 of plate C and in part in plate A. 



Circulatory System. 



The blood vascular or circulatory system in general consists of 

 several longitudinal vessels (dorsal, ventral and lateral), connecting 

 blanches in each somite, vessels to the nefritfia and other organs, 



