DUTROCHET’S LAND LEECH IN ENGLAND. 517 
stomach which precedes it, and from the rectum which follows 
it; 4th, the rectum, of which the lining membrane is reddish, 
communicating with the excretory orifice. 
The alimentary canal is quite straight. The heart, like the 
blood-vessels, is filled with red blood, and the annular swelling— 
in the middle of which the heart is situated—receives a great 
number of these vessels. This led Dutrochet to regard it as an 
organ of respiration, akin to lungs. He could discover no trace of 
those little pouches which, to the number of niue on each side, 
are found in the Medicinal Leech, Hiruwdo medicinalis.* 
With regard to the habits of Trochetia, Dutrochet states that it 
does not live in the water, but on moist soil, where it pursues 
earthworms, on which it preys, and which it swallows piecemeal 
(par trongons).t When placed in water he found that it died in 
three or four days—a statement, however, which has received 
some modification at the hands of later observers. On the whole 
Dutrochet considered that the annelid in question constitutes a 
genus intermediate between the Karthworms and the Leeches, but 
nearer to the latter than to the former. 
The few authors who immediately succeeded Dutrochet in 
noticing this annelid, as Lamarck and De Blainville, apparently 
added little or nothing from their own observation to what had 
previously been made known concerning it. Lamarck corrected 
Dutrochet’s generic name from Trocheta to Trochetia,} and after 
pointing out that the genus is distinguished from Hirudo by 
having the mouth bilabiate, and possessing neither teeth nor eyes, 
he gives the following salient characters :—‘ Body long, cylin- 
drical, anteriorly larger, and somewhat flattened posteriorly, and 
* Leeches have no special organ of respiration, the function being performed by 
the entire skin, and the organ in Hirudo, Aulastoma and Hemopis, which Lamarck 
and others thought were two rows of respiratory pouches, and which are absent in 
Trochetia, are apparently only reservoirs of mucus, perhaps for lubricating the skin. 
+ Other observers have remarked that, like dulastoma, it swallows the worm 
whole. On examining one of two specimens which Professor Garrod found in the 
Regent's Park and kindly submitted to me, I drew from its mouth a portion of a 
small earthworm, which measured fully an inch in length. 
¢ Agassiz, in his ‘ Nomenclator Zoologicus,’ gives the derivation of this word as 
70x05 = discus, a plausible but erroneous idea, for it is evident that the genus was 
intended to be named after its author, but the termination was incorrectly formed 
by him. Moquin Tandon, however, retains the original spelling, as also does 
Diessing, in his ‘Systema Helminthum,’ vol. i., p. 459 (1850), and Johnston, Cat. 
Brit. Non-parasitical Worms in Brit. Mus., p. £0 (1865). 
