20 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
alcohol, allowing it to act until the specimens have a light rose color, 
then wash well in neutral alcohol (90%), clear in cedar oil, and mount 
in balsam. 
III. CLASSIFICATION. 
Leeches of the family Rhynchobdellidz may be distinguished from all 
others by the fact that they possess an exsertile proboscis ( pr’d., Figure 1), 
with the aid of which they obtain their food, for they are entirely with- 
out jaws such as the medicinal leech possesses. Our common North 
American species of this family belong to the genus Glossiphonia John- 
son (16), better known to many by its synonym Clepsine Savigny 
(20). Leeches of this genus have usually a broad flat body, which, 
when the animal is disturbed, is rolled into a ball. Each somite con- 
sists typically of three distinct rings; but the somites at the ends of the 
body always contain a smaller number of rings. 
These leeches are found in the shallow water of ponds and rivers 
underneath stones, sticks, or leaves, or adhering to the bodies of their 
hosts. The smaller species feed upon snails, crustacea, or other small 
fresh-water animals; the larger species are known to feed upon turtles, 
to whose shells they are often found attached. They probably suck the 
blood of other aquatic animals also. 
The following key may aid in distinguishing the species to be 
described : — 
Key to Species. 
A. Crop diverticula a single pair (after a full meal the animal may have 
five more pairs, inconspicuous, and situated anterior to the prin- 
cipal pair) ; male and female genital pores separated by a single 
body ring ; rings without metameric markings in the living animal. 
1. Eyes two, distinct ; a conspicuous yellowish brown chitinous 
spot on the neck dorsally . . . . . . G. stagnalis (p. 21) 
2. Eyes two, inconspicuously pigmented or entirely without pig- 
ment ; no chitinous spot on the neck ; body extremely slender and 
transparent . . .. . . . « ~ | G. elongata (p39) 
B. Crop diverticula six pairs ; tice and female genital pores separated 
by a single body ring or else united. 
3. Eyes two, the middle (sensory) ring of each somite marked 
throughout the greater part of the body by a transverse row of 
whitish spots; .. 0 . ts 2 1 (= sa) Geer Gasca 
