W. A. Harding 
163 
Glossobdella bioculata, de Blainville, 1828, p. 565, pi. xxxvii, figs. 3, 3a and 3b; 
Gervais, 1836, p. 629, pi. ccxi, fig. 9. 
Erpobdella stagnalis, Templeton, 1836, p. 235. 
Clepsina stagnalis, de Filippi, 1837, p. 27 ; de Filippi, 1839, p. 6 ; Brightwell, 1842, 
p. 14. 
Glossiphonia bioculata , Moquin-Tandon, 1846, p. 366, pi. xiii, figs. 16—26 ; Thompson, 
1846, p. 390, footnote (recorded from Lough Neagh, Ireland); Houghton, 1861, 
p. 33 et seq., pi. iii, figs. 5 and 8 (cervical plate with parasitic Epistylis) ; 
Houghton, 1865, p. 82 et seq., pi. i, figs. 7—9 (coloured); Ninni, 1889; R. 
Blanchard, 1893d (in Norway); R. Blanchard, 1893k, p. 43 (occurrence in 
Azores). 
Glossiphonia circulans, Moquin-Tandon, 1846, p. 384. 
Glossipora bioculata, Thompson, 1856, p. 425 (occurrence in N. Ireland). 
Clepsine filippi, Polonio, 1863. 
Clepsine modesta, Yerrill, 1872, p. 679. 
Clepsine submodesta, Nicholson, 1873. 
Clepsine viridissima, Picaglia, 1877. 
Glossosiphonia stagnalis, R. Blanchard, 1894 b, p. 25 (diagnosis). 
Helobdella stagnalis, R. Blanchard, 1896a, p. 4 (occurrence in S. America); Johansson, 
1909, p. 76, figs. 131, 132. 
Glossiphonia stagnalis, Scharff, 1898, p. 191 ; Castle, 1900 a, p. 21, pi. i, figs. 1—3 
and pi. ii, fig. 4 ; Evans, 1905, p. 215 (occurrence in Scotland). 
Helobdella bioculata, Beyer, 1898, p. 648 et seq. (sense organs). 
Diagnosis. Body elliptic-lanceolate, much flattened, without 
papillae, more or less transparent, pale gray, often with a greenish, 
yellowish or brownish tinge, finely speckled with black. 68 rings. 
The two eyes are closely approximated (in an inner paramedian 
position) and lie upon the third ring or between rings 2 and 3. 
A rounded, brownish chitinous plate is situated in the dorsal 
median line, between rings 12 and 13. 
The male genital orifice lies between rings 24 and 25 ; the female 
orifice is situated one ring behind the male, between rings 25 and 26. 
Testes, 6 pairs. 
Eggs attached to the ventral surface of the parent. 
The anus lies behind ring 67 and is separated from the posterior 
sucker by the sixty-eighth and last ring, which is incomplete. 
Length, at rest, 8—12 mm.; width, at rest, about 4 mm. Length, 
fully extended, 23—26 mm. 
The length of the body in extreme extension may be as much 
as twelve times the width. 
Distribution, Food, etc. A small and active species common, and 
in some places abundant, in the British Islands, in lakes, ponds, ditches 
and sluggish streams, chiefly among aquatic plants. 
