1 PROF. E, A. MINCHIN ON PROTOZOAN [Jan. 12, 
a day or two, and then put them into bell-jar aquaria containing 
various fishes. Asa rule the Arguli attached themselves at once 
to the fish very firmly. After leaving them for varying periods I 
removed the Arguli and examined them, first living and uninjured 
under the microscope, and afterwards dissected in salt-solution 
and examined fresh. Although the fishes on which the Arqula 
fed contained trypanosomes or trypanoplasms in all cases, I never 
found a flagellate of any sort or description in the Arguli, how- 
ever the experiment was varied; and, moreover, I never in any 
case found the Arguli to contain blood-corpuscles. It might be 
supposed that an animal so transparent as Argulus would show 
the effects of a meal of blood by a change of colour visible to the 
naked eye; but in no case could a change of colour be discerned 
by any optical means whatsoever. I very much doubt, therefore, 
if Argulus feeds on blood, or at least on bloed-corpuscles. Very 
possibly only fluid plasma or lymph can pass the very minute 
terminal aperture of its proboscis. 
My experiments with leeches were greatly hampered by the 
fact, in the first place, that I can lay claim to no special knowledge 
of the Hirudinea, and secondly, that no general monograph of this 
group was accessible to me of later date than that of Moquin- 
Tandon (1846). It would bea great boon to those studying these 
parasites if a more recent monograph or handbook were in existence. 
It is not every student of hemoflagellates who is at the same time, 
like M. Brumpt, a first-class expert on leeches. I obtained a few 
specimens of Piscicola, but found nothing in them of flagellate 
nature. I put a Prscicola in an aquarium in company with a 
perch ; the leech took no notice of the fish, nor the fish of the 
leech. After some days I removed the leech, dissected it, and 
found nothmg in it. I also caught in the Broad some other 
leeches, which I could not identify accurately, and put them in 
with perch ; in all cases the leeches vanished completely, and were 
apparently eaten by the fish. Vozld tout! 
I can therefore make no positive additions to the transmission- 
question, but I hope to return again to this point when opportunity 
offers itself. 
Description of the Species. 
1. TRYPANOsoMA PERCH Brumpt. (Plate I. figs. 8-15; Plate V.. 
figs. 94-104.) 
Brumpt (CR. Soc. Biol. lx. 1906, p. 161) describes this species. 
as follows :—‘* Dans le sang de la Perche (Perca fluviatilis). Ce 
parasite mesure 57 de longueur totale, dont 16 pour le flagelle, 
et 3 de large. Le blépharoplaste est & 1u°5 de l’extrémité posté- 
rieure. Le noyau se trouve 4 égale distance de la racine du 
flagelle et de la partie postérieure.” 
I identify the trypanosomes found by me in the Perch as 
7’. perce Brumpt solely on the ground of occurrence, since Brumpt’s. 
description might apply to almost any trypanosome, and fails to 
