2O4 Introduction to AnimaL Morphology. 



under its abdomen for a \vhilr. I Lementeria has a mouth in 

 front, not in the middle, of the sucker, in a protrusible pro- 

 boscis ; both genital openings are on a common wart ; the 

 glands about the neck pour out an irritating secretion, which 

 cause urticaria in the human subject. Piscicola has a linear 

 body with wide anterior Lanital openings, and is not capable 

 of rolling itself up. 6. Hirudinidoe hermaphrodite; nar- 

 rowed in front and behind ; four or five rings on each mcta- 

 nierc ; an anterior sucker present ; pharvnx slightly protru- 

 sible, with three toothed ja\v> ; anus over the hinder sucker. 

 Pontobdella lias six eyes, and both suckers are on narrowed 

 ends ; the body warted, not ringed ; they are ecto-parasitic 

 on Fishes. I'.rancliellion has, on each edge, twenty-six leaf- 

 like processes; they are not ringed, and have 4-8 eyes ; living 

 on the gills of the Turbot and Torpedo, cS:c. Ichthyobdelki 

 is elongated, obsoletely ribbed, with 4-8 ocelli and sub- 

 elliptic suckers. I LeniM]i-is lias ten eyes and jaw- 

 hardened folds of the pharynx. The.se do much mischief, as, 

 when young, they are taken in by cattle with the water which 

 they drink, and attach themselves to the pharynx, and even 

 may enter the wind-pipe. Trochetia has toothless jaws, and 

 .ital openings between the 32-3 and 37-8 rings. Aula- 

 :oimim (Horse-leeches) are cylindrical, with the hinder 

 lip of sucker obliterated: -mall, or none; intestine 



wide ; anu.s large ; genital openings in males between 24-5 

 rings, in females 29-30. Ilirudo has the lirst disc ringed, 

 not separated by a constriction from the flattened body ; < 

 10 ; jaws 3, semilunar, with 30-100 teeth, and 100 rings on 

 the body. 11. medicinalis, the German leech, is dark gr< 

 with black spots below. H. officinalis, the Hungarian leech, 

 is olive green, without spots below ; each jaw has 70-90 teeth 

 h, with two roots. The sex-openings are as in Aulacosto- 

 mum. They take three years to become sexually mature, and 

 live 18-20 years. The cocoons are laid in summer and 

 winter, and the young embryo begins to creep in 4-6 weeks. 

 A few retain the cocoons attached to their bodies, thus ap- 

 pearing viviparous. 



The thirst for blood in leeches can be increased by putting 

 them in a mixture of wine and water, or one part of vinegar 



