ABRANCHIATE. 
143 
FAMILY II. 
abranchiate: asetigere:. 
The second family consists of two great genera, botli of which are 
aquatic. 
Hirudo, Lin. 
Leeches have an oblong, sometimes depressed, transversely plicated 
body ; the mouth is encircled by a lip, and the posterior extremity 
furnished with a flattened disk, both of which are well adapted for 
adhering to bodies by a sort of suction, and are the principal organs 
of locomotion possessed by these animals ; for after extending itself, 
the Leech fixes its anterior extremity and approximates the other, 
which in its turn adheres to allow the former to be carried forward. 
In several Ave observe on the under part of the body two series of 
pores, the orifices of as many small internal pouches, considered by 
some naturalists as organs of respiration, although they are usually 
filled with a mucous fluid. The intestinal canal is straight, inflated 
from space to space, for two-thirds of its length, Avhere there are two 
ciEca. The blood SAvalloAved is preserved there, red and unchanged, 
for several Aveeks. 
The ganglions of the neiwous cord are much more separate than in 
the Lumbrici. 
The Hirudines are hermaphrodites. A large penis projects from 
under the anterior third of the body, and the valve is a little further 
behind. 
Several of them form their eggs into a cocoon, and envelope them 
Avith a fibrous ‘excretion *. 
They have been subdivided from characters principally drawn 
from the organs of their mouth. In the 
Sanguisuga, (Say. f 
Or the Leech pjroperly so called, the superior lip of the anterior 
cup or sucker is divided into several segments ; the aperture is trans- 
verse and contains three jaAVS, each edge of Avhich is armed with tAA'o 
roAA's of very fine teeth, Avhich enables them to penetrate through the 
skin Avithout causing a dangerous Avound. It is marked Avith ten 
small points, considered as eyes. 
We all knoAV the medicinal or common Leech — Hiriido me- 
dicinalis, L., that useful instrument for the local abstraction of 
* See Memoires pour servir a VHist. Nut. lies Sangues, by P. Thomas ; a Memoir 
of Spix, Acad. Bav., 1813 ; and a third of M. Carena, Acad. Turin., t. XXV ; but 
especially the Sgsteme des Annilides, Savigny, and the Monographie des Hirudmes, 
Moquin-Tandon, Montpellier, 1826, 4to. See also Esssai eVune Monographie de la 
famille des Hirudinies, extracted from the Diet, des Sc. Nat. by M. de Blainv., 
Paris, 1827, Svo., and the article Sangsue of the same Avork, by Audouin. 
-j- M. de Blainville changes this name into Jatrobelle. For the various medi- 
cinal Leeches, see the fig. of Messrs. Carena, Acad. Turin., t. XXV, pi. xi, and Mo- 
quin-Tandon pi. v. 
