516 THE ZOOLOGIS'Y. 
Trochelia subviridis was first noticed by Dutrochet, in 1817, 
from specimens obtained near Chateau-Renaud, in the Department 
dIndre et Loire, where it was stated at that time to be tolerably 
common.* He has described it as resembling a Leech in ap- 
pearance, horizontally flattened like one, and similarly provided 
with a contractile disc at the posterior extremity; but differing 
from it in wanting the three teeth, with which leeches puncture the 
skin of their prey, and in possessing, on the anterior third of the 
body, an annular enlargement or swelling (xenflement), analogous 
to what is seen in the common earthworm. 
The length of this annelid varies considerably, individuals 
having been met with which measured from two to six inches. 
The colour in general is greyish green, somewhat lighter beneath, 
as well as on the annular enlargement, while on the back are two 
longitudinal and parallel brown lines, scarcely noticeable at first, 
but which become more perceptible on immersion in alcohol, when 
the whole body, with the exception of these two lines, turns to a 
dull leaden colour above, and a pale clay-colour beneath. The 
late Dr. Baird, of the British Museum, on making this experiment 
with some British specimens, found that the colour left the leeches 
and imparted itself to the spirit, which became of a fine green hue. 
The mouth is large and bilabiate, the upper lip being somewhat 
larger than the under one, and according to Dutrochet—and after 
him Lamarck t—there are neither teeth nor eyes. But upon the 
question of the presence or absence of teeth and eyes later 
authorities differ, as I shall presently point out. 
The excretory orifice, which is large as compared with what 
obtains in the true leeches, is situated on the median dorsal line, 
a little above the posterior disc; the genital organs are placed 
beneath, in the middle of the annular enlargement. 
But it is in its internal anatomy especially that this animal 
differs from the true leeches. 
The alimentary system consists—Ist, of a long smooth eso- 
phagus, disposed in longitudinal folds; 2nd, a stomach of which 
the lining membrane is villous and of a greyish colour; 3rd, the 
intestine shorter than, and as large as, the stomach, with the lining 
membrane of a fine yellow colour, a valve separating it from the 
* Dutrochet, “ Note sur une Annélide d’un genre nouveau”; ‘ Bulletin des Sciences 
par la Société Philomatique de Paris,’ 1817, p. 130. 
+ ‘ Hist. Nat. des Anim. sans Vertébres,’ 2nd. ed., 1838, vol. v., p. 522. 
