140 
The British Leeches 
Piscicola geometra, Linnaeus, 1761. 
Plate XIII, Figs. 4, 5, 6. Text Fig. 2 (p. 135). 
Synonymy and Literature: 
Hirudo alba perexigua piscibus adhaerens, Aldrovandus, 1602, p. 722. 
Hirudo ore caudaque ampla, Frisch, 1729, p. 25, pi. ii; Ledermiiller, 1764, pi. lxxxvii, 
figs, a—i. 
Hirudo teres extremitatibus dilatatis, Linnaeus, 1746, p. 365, No. 1275. 
Hirudo piscium, Rosel von Rosenhof, 1747, p. 199, pi. xxxii, figs. 1—4; Bergman, 
1757, p. 310 ; 0. F. Muller, 1774, p. 43 ; O. F. Muller, 1776, p. 220; Gmelin, 1788 , 
p. 3097; Brugui&re, 1824, p. 133, pi. li, figs. 12—19 (after Rosel); Bose, 1802, 
p. 257 ; Pennant, 1812, p. 70, pi. xxi, fig. 3 (after Rosel); Stewart, 1817, p. 357; 
Ray Society Reports, 1845, p. 286. 
Hirudo dor so elevato, cauda latiore—the great tailed Leech , Hill, 1752, p. 17 ; 
Linnaeus, 1758, p. 650. 
Hirudo geometra , Linnaeus, 1761, No. 2083; Weser, 1765, p. 44; Linnaeus, 1767, 
p. 1080, No. 8; Barbut, 1783, p. 20, pi. ii, fig. 7; Pennant, 1778, p. 38, pi. xx, 
fig. 13; Turton, 1806, p. 70; Tux’ton, 1807, p. 129; Pennant, 1812, p. 70, pi. xxi, 
fig. 3; Johnson, 1816, p. 35; Brightwell, 1842 a, p. 11, pi. i, figs. 1—8 (coloured); 
Brightwell, 1842 b, p. 65. 
Hirudo galearia, Braun, 1805, p. 35, pi. iii. figs. 1—3 (coloured). 
Piscicola piscium , de Blainville, in Lamarck, 1818, p. 294; Milne-Edwards, in 
Lamarck, 1838, p. 525; Stark, 1828, p. 142; Apfithy, 1888 a, p. 154 et seq., 
pi. viii, fig. 8 (diagram of somite); Ap&thy, 1888 b, p. 774 et seq. ; Ap&thy, 1889, 
p. 305 (complete somite has 14 rings). 
Haemocharis piscium, Savigny, 1822, p. 112. 
Piscicola geometra , Moquin-Tandon, 1826, p. 131, pi. vii, fig. 1; Fleming, 1822, p. 604; 
Leo, 1835, p. 419, pi. xi (anatomy); Henle, 1836, p. 220; Thompson, 1844, 
p. 437 (occurrence in Ireland) ; Johnston, 1846, p. 441 ; Grube, 1851, p. 112 ; 
Thompson, 1856, p. 426 (occurrence in Ireland); Johnston, 1865, p. 43; 
Blanchard, 1894 b, p. 18; Johansson, 1897; Johansson, 1898 a, p. 677; 
Johansson, 1898 b, p. 581 et seq., fig. 19 (nephridium); Scharff, 1898, p. 190; 
Plehn, 1898, p. 370; Montgomery, 1899; Brumpt, 1900, p. 47, fig. 1, A—D 
(cocoon); Castle, 1900, p. 298 (somite growth); Selensky, 1906, p. 33; 
Johansson, 1909, p. 70, figs. 115—117. 
Ichthyobdella geometra, de Blainville, 1827, p. 244; de Blainville, 1828, p. 558, 
pi. xxxiv, figs. 5, 5 a; Gervais, 1836, p. 628, pi. ccxi, fig. 8; Diesing, 1850, p. 440. 
Ichthyobdella percae, Templeton, 1836, p. 236, fig. 28 a, b and c (woodcuts) ; Diesing, 
1850, p. 442. ■ 
Ichthyobdella piscium, Egidy, 1844, p. 107, pi. iv, fig. 73. 
Piscicola percae, Johnston, 1846, p. 441; Thompson, 1856, p. 426 (occurrence in 
Ireland); Johnston, 1865, p. 43. 
Diagnosis. Body soft and semitransparent, of nearly uniform width 
posteriorly, attenuated anteriorly, in extension as much as twenty times 
as long as broad. Anterior sucker circular, about half as wide as the 
