146 
The British Leeches 
Genus: Protoclepsis, Livanow, 1902. 
Synonymy: 
Glossipkonia, Johnson, 1816 (partim). Clepsine, Savigny, 1822 (partim). Haemo- 
charis, de Filippi, 1837 (partim ; nni Haemockaris, Savigny, 1822). Theromyzon , 
Philippi, 1867. Hemidepsis, Yejdovsky, 1883 (partim). (?) Protodepsine , 
Moore, 1898. 
Glossosiphonidae of medium size, with four pairs of eyes. Complete 
somite formed of three rings. Somites III—XXIII are complete. 
Crop with more than six pairs of many-lohed lateral caeca, the last and 
longest pair reflected posteriorly. “ The presence of two nuclei in each 
muscle cell is a special peculiarity ( Livanow.) 
This genus has been created by Livanow (1903, p. 339) in order to 
admit P. tessellata, a species formerly included in Hemiclepsis (q.v.) and 
several eight-eyed forms occurring for the most part in Lake Baikal. 
These comprise a well-defined and homogeneous little group, the 
members of which are somewhat difficult to distinguish one from 
another. This close similarity, if we are to believe Livanow, has 
led to the confusion of two species under the name Hirudo tessellata 
(O. F. Muller 1774.) Such a possibility had already been contemplated 
by Blanchard (1892, p. 62.) The species which Livanow has isolated 
from the H. tessellata of previous authors has been described by him 
under the name of Protoclepsis meyeri. The genus Protoclepsis is 
divided by its author into two groups characterized as follows: 
A. Genital apertures separated by two rings. A primitive form 
of vagina is present in adults. It is undeveloped in young individuals 
and the oviducts opening directly to the exterior on either side of the 
ventral median line appear as two separate female genital apertures. 
B. Genital apertures separated by more than two rings. The 
female opening is the single aperture of a well-developed vagina. 
P. meyeri falls within the first and P. tessellata within the second 
of these groups. 
The synonymy of P. tessellata and P. meyeri is inextricably confused, 
since the inadequacy of the descriptions given by most writers renders 
it impossible to determine which of these two species they had in view. 
Only Malm and R. Blanchard have noted the position of the genital 
orifices; to the latter we owe the first satisfactory diagnosis of P. 
tessellata, whilst in the description of Malm (1860) we have the only 
positive record of P. meyeri in Western Europe. 
