CASTLE: NORTH AMERICAN RHYNCHOBDELLID®. 53 
(middle) pair is closely united with sensille situated in the first ring of so- 
mite 11. (Figure 2), a fact which Whitman (’92) established for ‘¢ C. hollensis” 
and which I can completely confirm for the species under discussion (Figure 2), 
Whitman (’92) further established the fact that the anterior pair of eyes 
in “hollensis”’ originates in connection with the sensille of somite um. He 
gives no statement as to the origin of the posterior pair. Comparison with G. 
elegans (Figure 29), however, leads me to regard this pair as probably derived 
from the sensillee of somite Iv. If so, the condition of the eyes in parasitica 
can be derived in its entirety from that found in G. elegans by supposing that 
both the anterior and the posterior pairs of eyes have become rudimentary and 
been brought close to the large middle pair. 
The mouth (or., Figure 2) apparently lies between somites I. and 11. ; in other 
species it lies farther back, usually in the anterior part of somite 111. The oral 
sucker is formed by somites I.-IV., as in other species. 
d. REPRODUCTIVE ORGANS. 
The genita? pores are situated in this species exactly as in G. elegans; the 
male (po. @, Figure 36), between somites xI. and XII. (rings 27 and 28) ; 
the female (po. 9), between the middle and posterior annuli of somite x11. 
(tings 29 and 30). 
XA.) SXVEL. 
Testes, six pairs situated intersegmentally in somites ——— _ 
, the usual 
Vee eRKe 
position in the genus. 
The eggs are large, white, and opaque. In the vicinity of Cambridge they 
are laid in May and June, perhaps also in July. In the case of those animals 
which laid in the laboratory, the eggs appeared to be attached loosely in a sin- 
gle group of fifty or more to the side of the aquarium, rather than to the body 
of the leech as is the case in the other species studied. The leech remained 
closely arched over the eggs, —a position from which it was removed only 
with great difficulty. 
e. Digestive Tract. 
The digestive tract resembles very closely that of G. elegans, but has one 
strikingly distinctive feature : the salivary glands (gl. sal., Figure 36), instead 
of being distributed through several somites in the crop region, are closely 
aggregated into two compact groups in each half of the body, these groups lying 
symmetrically, a pair on either side of the proboscis, within somites 1x.—xI. 
1 On account of this and other close structural agreements with “ C. hollensis ” 
as described by Whitman (’92), I was for some time inclined to regard that name 
as well as “ chelydra ” as a synonym with parasitica, and I have so treated it in a 
recent publication (Castle, 1900). Professor Whitman, however, has subsequently 
informed me ina letter that in hollensis “there are several pairs of pigmented eyes 
behind the pair usually recognized as ‘eyes.’ These are quite conspicuous in the 
living leech, and I have never seen any such feature in other Clepsines.” This 
being so, it is probable that hollensis should rank as a distinct species. 
