the Hirudo complanata and Hirudo stagnatis. 343 
minating that extremity. Thus securing its hold, it draws up 
the tail, when the back describes an arch, as in Fig. 6. The 
tail is then fixed by a similar sucker, and the head is again 
extended. Now and then it supports itself by the tail, the 
head waving to and fro, and occasionally buries its head 
under the abdomen, somewhat after the manner of an oniscus. 
This is seen in Fig. 7. 
The G. punctata is much smaller than the above, and ex- 
ceedingly delicate in its structure. On the head, we notice 
two eyes, placed transversely (Fig. 13. b). It is delineated 
of its natural size, in Fig. 11, 12. Both the back and belly 
is of a dusky grey, profusely sprinkled with minute black 
specks. 
The stomach of the G. tuberculata, like that of the leech, 
is divided into several cells or partitions (Fig. 10. d. e.) with 
their extreme points verging towards the tail. The two last 
of these cells (/) are much longer than the rest, and ter- 
minate in two blind sacs. Between them, we notice the in- 
testine, a tortuous tube extending to the anus, ( Fig. 9. e. ) a 
foramen above the rim of the circular sucker, or what con- 
stitutes the tail. 
These animals, it has been asserted, when cut, or divided, 
are capable of reproduction, but this seems to rest on no just 
foundation. 
Their food principally consists of the water helices , and 
here we see the great use of the projectile tubular tongue. 
The animal, from its tapering so much towards the head, is 
enabled to penetrate some considerable way into the hollow 
of the shell, and from the flexibility of its tongue, can follow 
its victim to the innermost recess of its habitation. A passage 
mdcccxvii. Y y 
