4o8 



HIRUDINEA 



CHAP. XIV 



parts of the continent. It is a land-leech, and lives upon earth- 

 worms. 



The genus Haemadipsa, which M. Blanchard places in a 

 special sub -family, contains a number of species which are 

 for the most part land- leeches. Land -leeches occur in many 

 parts of the world, but chiefly in the tropics in India, Ceylon. 

 Java, South America, etc. They lie in wait for their prey, upon 

 the ground as a rule ; but they may ascend herbs and shrubs to 

 gain a better outlook when they are aware of an approaching 

 footstep. A vivid account of the ferocity of these tiny Annelids 

 in Ceylon can be read in Sir J. E. Tennent's Natural History of 

 Ceylon. They have been said to be so pugnacious and so poison- 

 ous that persons surprised in their sleep by the pests have suc- 

 cumbed to their united efforts. A whole battalion of English 

 soldiers decamped on one occasion from a wood which was over- 

 flowing with land-leeches. The familiar misquotation " lethalis 

 hirudo " might well be applied to this species. Professor Whit- 

 man has written much upon the habits of the land-leech of Japan 

 (Haemadipsa japonica), which bites so softly that its presence 

 cannot be detected except for the stream of blood which trickles 

 from the wound. While it is feeding it emits from the pores 

 of the nephridia a clear fluid, which, as it appears, is used to 

 keep the skin moist ; when unduly dried the same phenomenon 

 occurs. It is curious that in this and other leeches the nephridia 

 should play a part which in the earthworm is played by the 

 dorsal pores ; in both animals the glands of the skin are also 

 concerned with the same duty. 



The purely aquatic leeches swim by undulations, and also 

 crawl by the help of the two suckers, like a " Geometer " caterpillar. 

 But when a land-leech is dropped into the water it at once sinks 

 to the bottom and crawls out ; it does not swim, but can survive 

 immersion for a long period. In this it resembles the earthworms, 

 which can also survive a prolonged immersion, and even in the 

 case of some are indifferent to the medium, land or water, in which 

 they live ; the land-leech, however, is entirely dependent upon 

 damp surroundings ; a dry air is fatal to it. The land-leech of 

 Japan leaves a slimy trail behind it as it crawls, in this respect 

 recalling the land Planarian Bipalium kewense. 



