134 
The British Leeches 
Marine leeches, ectoparasitic on fish. Body flattened, the posterior 
region with lateral, paired, foliaceous, non-digitate branchiae. Suckers 
cupuliform, excentrically attached, the posterior very large and studded 
upon its inner surface with numerous, small subsidiary suckers. Complete 
somite formed of three rings. 
This genus is represented in European waters by a single species 
(Blanchard, 1894 a, p. 85). 
Branehellion torpedinis, Savigny, 1822. 
Plate XIII, Figs. 1, 2, 3. Text Fig. 1. 
Synonymy and Literature: 
Branehellion torpedinis , Savigny, 1822, p. 109 ; Risso, 1826, p. 432; Savigny, 1826, 
p. 451 ; Moquin-Tandon, 1826, p. 141 ; Milne-Edwards, in Lamarck, 1835, 
p. 529 ; Cuvier, 1836, p. 51, pi. xxiii, tig. 3; Moquin-Tandon, 1846, p. 282, pi. i, 
figs. 1—10 (coloured); Leydig, 1851, p. 315, pi. ix, fig. 1 (anatomy of brancliia); 
Grube, 1851, p. 108; Johnston, 1865, p. 38 (recorded from England); Apathy, 
1888 a, p. 153, etc., pi. viii, fig. 1 (diagram of annulation, etc.), and fig. 11 (de¬ 
tails of branchiae); R. Blanchard, 1894 a, p. 85 ; R. Blanchard, 1894 b, p. 11; 
Ap&thy, 1901 a, p. 211 (neurofibrillae); Apathy, 1901 b, p. 707 (histology of light 
sensory cells) ; Perez and Gendre, 1904 a, p. 113 (muscle fibres); ibid. 1904 b, 
p. 605 (ovogenesis) ; Perez, 1906, p. 447 ; Holt, 1907, p. 102 (recorded from 
Ireland). 
Hirudo ( Branchiobdella ) rudolphii, de Blainville, 1827, p. 241. 
Branchiobdella rudolphii , Diesing, 1850, p. 443; Polonio, 1863. 
Branchiobdella torpedinis , de Blainville, 1828, p. 556, pi. xxxiv, figs. 1, 1 a and 1 b. 
Hirudo ( Branchiobdella ) torpedinis , Gervais, 1836, p. 627, pi. ccxi, fig. 1. 
Branchellia torpedinis , Gervais, 1845, p. 573. 
Branehellion orbinensis, de Quatrefages, 1852, p. 279, pi. vi, fig. 1 and figs. 2—13 
(anatomy). 
Branehellion rhoinbi, van Beneden and Hesse, 1863, p. 33, pi. ii, figs. 17—21 (bad). 
Diagnosis. The two regions of the body are sharply defined. The 
anterior'is partly invaginated into the posterior region, the first ring of 
which forms a fold surrounding and overlapping the posterior half of 
the clitellum. [Apathy (1888 a, p. 170) has pointed out that this fold 
is really composed of two rings, one lying upon its outer and one upon 
its inner surface. These two rings, which form somite XIII, lie one in 
front of the other in very young individuals and are gradually gathered 
up into a “preputial fold” as maturity is approached.] Colour brownish 
black, with six longitudinal series of yellowish white spots on the dorsal 
and four on the ventral surface; the spots occur on the first ring of each 
