234 LOWER INVERTEBRATES. 



coons or egg-capsules, in each of wliicli are several yolks, so that, when the young 

 hatch out at the end of fi\e or six weeks, several are born at once, and immediately 

 make their way to the water. They grow very slowly. It is said that five years 

 elapse before they attain tlieir full size ; they may live for twenty years. 



Our waters contain many leeches similar to Hirudo ; most of them belong to the 

 genera Nephelis and Hcemopis. A giant among them is the big, spotted Macrostomum 

 of our ponds. In southern Asia there live also terrestrial forms. 



" Of all the plagues," writes Sir J. Emerson Teunent in his charming book on 

 Ceylon, "which beset the traveller in the rising grounds of Ceylon, the most detested 

 are the land leeches {Hmmadipsa ceylonica). They are not frequent in the plains, 

 which are too hot and dry for them, but amongst the rank vegetation in the lower 

 ranges of the hill country, which is kept damp by frequent showers, they are found in 

 tormenting profusion. They are terrestrial, never visiting ponds or streams. In size 

 they are about an inch in length and as fine as a common knitting needle; but 

 they are capable of distension till they equal a quill in thickness, and attain a length 

 of neaily two inches. Their structure is so flexible that they can insinuate themselves 

 through tlie meshes of the finest stocking, not only seizing on the feet and ankles, but 

 ascending to the back and throat, and fastening on the tenderest parts of the body. 

 In order to exclude thera, the coffee planters, who live among these pests, are obliged 

 to envelop their legs in 'leech-gaiters' made of closely woven cloth. The natives 

 smear their bodies with oil, tobacco, ashes, or lemon juice, the latter serving not only 

 to stop the flow of blood, but also to expedite the healing of the wounds. In moving, 

 the land leeches have the power of planting one extremity on the earth and raising the 

 other perpendicularly to watch for their victim. Such is their vigilance and instinct, 

 that, on the approach of a passer-by to a spot which they infest, they may be seen 

 amongst the grass and fallen leaves on the edge of a native path, poised erect, and 

 prepared for their attack on man and horse. . . . Their size is so insignificant, and 

 the wound they make is so skilfully punctured, that both are generally imperceptible, 

 and the first intimation of tlieir onslaught is the trickling of the blood, or a chill feel- 

 ing of the leech when it begins to hang heavily on the skin from being distended with 

 its repast. Horses are driven wild by them, and stamp the ground in fury to shake 

 them from their fetlocks, to which they hang in bloody tassels. The bare legs of the 

 palankin bearers and coolies are a favorite resort ; and as their hands are too much 

 engaged to be spared to pull them off, the leeches hang like bunches of grapes round 

 their ankles. . . . Both Marshall and Davy mention that during the march of 

 troops in the mountains, when the Kandyans were in rebellion, in 1818, the soldiers, 

 and especially the Madras Sepoys, with the pioneers and coolies, suffered so severely 

 from this cause that numbers perished." 



" One circumstance regarding these land-leeches is remarkable and unexplained ; 

 they are helpless without moisture, and in the hills, where they abound at all other 

 times, they entirely disappear dui-ing long droughts; yet reappear instantaneously 

 at the very first fall of rain, and in spots previously parched, where not one was visi- 

 ble an hour before, a single shower is sufficient to reproduce them in thousands. 

 Whence do they re-appear ? May they, like the rotifers, be dried up and preserved 

 for an indefinite period, resuming their vital activity on the mere recurrence of mois- 

 ture?" 



The second family is distinguished by having a proboscis, and has, therefore, been 

 named Rhtnchobdblijd/e, of which the very common fresh-water Clepsine is a good 



