152 
The British Leeches 
Piscicola marginata, Moquin-Tandon, 1826, p. 133, pi. vii, fig. 2. 
Piscicola tesselata, Moquin-Tandon, 1826, p. 133. 
Glossobdella cephalota, de Blainville, 1827, p. 266. 
Ichthyobdella marginata, de Blainville, 1828, p. 558. 
Haemocharis marginata , de Filippi, 1837, p. 26. 
Clepsine marginata, Fr. Muller, 1844, p. 377, pi. x, fig. 4; Diesing, 1850, p. 447; 
Apathy, 1888a, p. 154, etc., pi. ix, fig. 1 (head); Apathy, 1888b, p. 789, etc.; 
Whitman, 1878, p. 2 et seq. (development); Leuckart, 1894, fig. 280 (digestive 
tract); Oka, 1894, p. 81 et seq., pi. v, fig. 24, etc. (sinus system, nephridia). 
Glossiphonia marginata, Moquin-Tandon, 1846, p. 375, pi. xiv, figs. 10—20; Houghton, 
1860, p. 248, pi. xvi, C, figs. 1, 2 (first record in England) ; Houghton, 1861, 
p. 34, pi. iii, fig. 15 (coloured); Houghton, 1865, p. 83, pi. i, fig. 10 (coloured); 
K. Blanchard, 1892 b, p. 173 (description). 
Hirudo jlava—the Yellow Leech, Dalyell, 1853, p. 45, pi. v, figs. 1—19 (coloured). 
Glossiphonia jlava, Johnston, 1865, p. 53. 
Diagnosis. Body claviform, flattened and more or less transparent. 
With the exception of the margins and anterior extremity, which are 
colourless or hyaline, the ground colour is pale yellow, variegated above 
with orange, reddish brown, lemon yellow and an intense green. Usually 
the green pigment predominates; there is however a form in which it 
is entirely absent, leaving the body yellow. The general colouration is 
considerably modified when the crop is distended with blood. Green or 
reddish brown transverse stripes traverse the clear margins of the first 
rings of each somite. 
Dorsal surface with seven longitudinal series of lemon yellow spots. 
The spots composing four of these rows occur on the first rings of each 
somite and correspond to the outer paramedian and intermediate sense 
organs. 
The spots composing a median row fall upon the second rings of each 
somite, whilst those forming the two remaining series occupy a para- 
marginal position and occur on both the second and third rings of each 
somite 
These spots are subject to individual fluctuations in size and may 
not all be present. The right and left paramarginal spots in each 
somite not infrequently are fused together, forming irregular C-shaped 
markings. 
Low papillae correspond to the outer paramedian and intermediate 
sense organs and spots on the first ring of each somite. 
Ventral surface without spots or papillae. 
Posterior sucker with a paramarginal row of lemon yellow spots, 
between which reddish brown rays frequently appear. 
