10 ; HIRUDO. 
appearance is limited to no particular season. The latter were larger 
than the others, being about the sixteenth of an inch in diameter. 
Though preserved a long time, they did not undergo any change ; and 
as nothing tended to elucidate their nature, I ceased to consider them as 
connected with the propagation of the leech. Some are represented 
Plate I. figs. 17, 18, 19, natural size ; and fig. 20, enlarged. 
Some capsules, of an oval form, have been seen in vessels containing 
similar leeches. 
Nothing of a particular interest has been disclosed by these animals ; 
some are in more active motion than above described, though still ad- 
hering by the sucker, which has appeared very thin and transparent. 
In certain positions, the microscope discovers that the body consists of 
numerous annulations. 
Some specimens being replete with blood on coming from the sea, 
the sustenance of those animals may be considered as probably derived 
from sources similar to that of the Hirudo muricata. 
Their faculties are certainly very obtuse ; or a particular state is 
attended with particular incapacity. If left dry above the surface of the 
water, they do not descend in quest of it, but remain on the spot to 
perish. 
Fig. 2 represents a group of smaller leeches, which may be the same 
as the preceding in earlier stages ; but their features were not equally 
definite, farther than in the appearance of the sucker. 
An animal somewhat of the same character is represented in the 
Dictionnaire d’Histoire Naturelle. I can scarcely presume to identify 
mine with that represented by Chamisso and Eysenhardt in the Nova 
Acta Physico-Medica, Academie Leopoldino Caroline Nature Curiosorum, 
tom. x. p. 350. ; tom. xxiv. fig. 4, Brusiz, 1821. 
Prats I. 
Fic 16. Hirudo vittata. 
17. 18, 19. Supposed capsules, natural size. 
20. Three capsules, enlarged. 
. 21. Group of leeches, supposed the same as fig. 16. 
