HIRUDINEA 137 
selves to her body.  Nephelis deposits its cocoons on water- 
plants, Aulostoma and Hirudo in damp earth. 
Leeches are usually inhabitants of fresh water; sometimes 
they live in salt water, and more rarely on land. They 
usually move in loops by the aid of their anterior and posterior 
suckers, but they can swim well. The land forms are most 
common in Asia south of the Himalayas, and in the East 
Indies and Australia. A gigantic form, Macrobdella Valdi- 
viana, lives underground in Chili, and is said to reach the 
length of 24 feet. They are, with few exceptions, parasitic, 
living on the blood of Vertebrates. 
The HrirupINEA are divided into two groups: 
(i.) Rhynchobdellidae.— Cylindrical or flat, elongated body 
with both suckers well marked, fore part of the body 
retractile, forming a proboscis. The vascular and the 
coelomic spaces are in direct continuity; the blood 
does not contain haemoglobin. Pontobdella, Clepsine, 
Piscicola. 
(ii.) Gnathobdellidae.—Mouth sucker-like, pharynx armed 
with three jaws. No proboscis. The vascular and the 
coelomic spaces are in indirect continuity. The blood 
contains haemoglobin. Hirudo, Aulostoma, Nephelis. 
