HIRUDO. 5 



The firm adhesion of the sucker to the skin of its prey must render 

 this animal a cruel and inveterate enemy. It is seldom detached by the 

 fishermen without suffering injury ; but when adhering to hard substances, 

 by inverting, it may be removed with comparative facility, by inserting 

 the edge of the thumb nail gradually under the sucker. 



During the day this singular leech reposes in absolute quiescence, but 

 towards evening, its wonted coil relaxes in wider curves, and it rears 

 itself erect on the plane of position, with the head turned inwards. 

 The quiescence of a solitary specimen, however, is interrupted by the 

 introduction of stranger leeches of its own kind ; their society is evident- 

 ly gratifying. Five having been collected in the same vessel, all began 

 to intertwine their necks together after fixing the sucker ; they stretched 

 and curved, or contracted the body, yet without shifting from their re- 

 spective spots of adhesion. Such movements continued for hours. 



Meantime, small and almost transparent vesicles, as it appeared, 

 each formed like a grain of oats, were observed protruding from the neck 

 of the animal. These extended about three lines ; each being connected 

 to the neck by a slender filament, also transparent. Two milk-white 

 parallel oblong substances were exposed within. 



The number of these vesicles is variable, according to the specimen. 

 In each of two a vesicle issued from that ring of the neck which was 

 next the lowest ; each of two others had three. In one of the leeches, 

 two vesicles, in near approximation, issued from the fifth or sixth row of 

 tubercles, lower than the neck. At first three appeared in the second 

 leech : and six or seven, some days later, whereof four then issued from 

 the neck. On the day subsequent, they seemed to have increased to 

 nine or ten. About five such objects were protruding from the neck of 

 a middle-sized specimen of the leech, on the day after being committed 

 to the vessel of a previous occupant ; and from the neck of its companion, 

 two of the same kind, appearing flaccid, which might have been mistaken 

 for two short horns. 



Authors have ascribed two short horns to the Skate Leech, under 

 which specific character, indeed, it stands in the Linnaean Systema Na- 

 tnrce. Farther, it is thus represented in BARBUT'S Genera Vermium, 



