NEPHELID^. 43 



thin margin : male orifice at the base of the neck, the female pos- 

 terior to it : vent very small, and scarcely visible. Lacustrine. 



1 . P. geometra, eyes eight, in pairs congregate on a fuscous spot ; 

 anal sucker rayed with fiascous, and marked between the rays with 

 eight blackish dots. Length 8-12'"; breadth 1-2'". 



Hiriulo teres extremitatibus dilatatis, Linn. Faun. Suec. 365. 

 Hiriido geometra, Linn. Syst. x. 650; xii. 1080; Faun. Suec. 2nd edit. 



506. Penn. Brit. Zool. iv. 38. pi. 20. f. 13. Turt. Gmel. iv. 70 ; 



Brit. Faun. 129. Johnson on Med. Leech, 35. Brightwell in Ann. 



Sf Mag. Nat. Hist. ix. 11. pi. 1. f. 1-8. 

 The Great-tailed Leech, Hill, Hist. Anim. iii. 17. 

 Hirudo piscium, Rbsel, Insect, iii. 199. tab. 32. f. 1-8. Miill. Verm. 



i. ii. 43; Zool. Dan. Prod. 220. Penn. Brit. Zool. iv. 70 (1812), 



pi. 21. f. 3. Stew. Elem. ii. 357. Ray Soc. Rep. 1845, 286. 

 Piscicola piscium, Lam. An. s. Vert. v. 294 ; 2de edit. v. 525. Stark, 



Elem. ii. 142. Moq.-Tandon, Monogr. 294. 

 Hsemocharis piscium, Savig. Syst. Annel. 111. 

 Ichthyobdella geometra, Blainville in Diet, des Sc. nat. xlvii. 244, 



& Ivii. 558. Gervais in Ann. des Sc. nat. vii. 56 (1837). Dies. 



Syst. Helm. i. 440. 

 Ichthyobdella piscium, Egidy, Bluteg. 107. pi. 4. f. 73. 

 Piscicola geometra, Flem. Phil. Zool. ii. 604. W. Thompson in Ann. 



Nat. Hist. xiii. 437. 



Ilab. In lakes, infesting the fish. 



Obs. M. Gervais asserts that the ocular points on the anterior 

 sucker, and the specks on the posterior sucker, are identical in 

 structure ! 



2. P. percSB, anal sucker vpith fourteen dusky rays and as many 

 black dots disposed circularly. Length 1"; breadth |-"'. 



Ichthyobdella percai, R. Templeton in Loud. Mag. Nat. Hist. ix. 236. 



f. 28. Dies. Syst. Helm. i. 442. 

 Piscicola perca;, Johnston in Ann. Sf Mag. Nat. Hist. xvi. 441. 



Ilab. "Found on a perch brought from Lough Neagh by Miss 

 Templeton." 



Fam. III. NEPHELID^. 



Obs. The rudimentary condition of the jaws disables the members 

 of this family from piercing the skin of animals. They are emi- 

 nently carnivorous, preying on worms, moUusca, and insect larvae, 

 which they swallow entire. The intestinal canal follows the cha- 

 racter which the nature of the food indicates ; — it is simple, without 

 lateral prominent lobes ; but in Aidostoina the stomach shows a 

 tendency to be sacculated, and has a pair of long appendages. The 

 s})ecies arc lacustrine, but they leave the water often, and live under 



