512 REPORT ON ZOOLOGY, MDCCCXL1V. 



be very useful to leeches, it is even said that the young in- 

 dividuals feed upon it, consequently it is good to place this 

 plant in the water with them, for at the end of eight or ten 

 days large quantities of green faeces are seen lying at the 

 bottom of the water, which Olivier maintains that he re- 

 cognised as the fragments of the Water-ranunculus. The 

 lancet-puncture in the leech closes after a few days, and it 

 can then be again employed for sucking ; in this way a 

 leech may always be reapplied after fifteen to eighteen days, 

 and but few die in consequence of the operation. Olivier 

 has done as much with thirty-five leeches as it would other- 

 wise have required 183 to effect. 



Guyon (Comptes reiidus, 1813, p. 424; or Institut. 1843, 

 p. 292 ; or Oesterreich. med. Wocheuschr. 1844, p. 125) has 

 again reported respecting Hcemopis vorax, the abundance of 

 which in Algeria is exceedingly troublesome, as these worms 

 crawl over man and beast. In one case a worm of this 

 species had crawled into the vagina of a soldier's wife at 

 Bona, and had caused a metrorrhagia. 



Among the Hirudinei, according to Thompson (Annals. 

 1. c. 13, p. 437), Piscicola geometra, Clepsine tessulata and 

 hyal'ma are indigenous in Ireland. In a dissertation (De 

 Hirudinibus circa Berolinum hucusque observatis. Diss. 

 Berol. 1844), by F. Miiller, the genera Clepsine, Nephelis, 

 Aulostoma, Sanyuisuya, Piscicola, and BranchiobdeUa are 

 characterized, and Clepsine marginata, tessulata, complanata, 

 hyal'ma, Carente and bioculata, species that occur near 

 Berlin, are described at length, and to these besides is added 

 the new species Clep. verrucata. The latter can be dis- 

 tinguished from Clep. complanata only by the internal struc- 

 ture. Clepsine verrucata possesses, for instance, " appeudicum 

 ventriculi paria 7, par ultimum inter appcndicum intestini 

 par primum et secundum terminatum ;" Clepsine complanata, 

 on the contrary, " appeudicum ventriculi paria 6, par ultimum 

 inter appeudicum intestini par secundum et tertium termi- 

 natum." In Clepsine complanata, Miiller observed, before 

 the expulsion of the ova, on both sides of the abdominal 



