512

REPORT ON ZOOLOGY, MDCCCXLIV.

be very useful to leeches, it is even said that the young in-dividuals feed upon it, consequently it is good to place thisplant in the water with them, for at the end of eight or tendays large quantities of green fseces are seen lying at thebottom of the water, which Olivier maintains that he re-cognised as the fragments of the Water-ranunculus. Thelancet-puncture in the leech closes after a few days, and itcan then be again employed for sucking; in this way aleech may always be reapplied after fifteen to eighteen days,and but few die in consequence of the operation. Olivierhas done as much with thirty-five leeches as it would other-wise have required 183 to effect.

Guyon (Comptes rendus, 1813, p. 424; or Institut. 1843,p. 292; or Oesterreich . med. Wochenschr. 1841, p. 125) hasagain reported respecting Hcemopis vorax, the abundance ofwhich in Algeria is exceedingly troublesome, as these wormscrawl over man and beast. In one case a worm of thisspecies had crawled into the vagina of a soldier’s wife atBona, and had caused a metrorrhagia.

Among the Hirudinei , according to Thompson (Annals.1. c. 13, p. 437), Piscicola geometra, Clepsine tessulata andhyalina are indigenous in Ireland . In a dissertation (DeHirudinibus circa Berolinum hucusque observatis. Diss.Berol. 1844), by F. Muller, the genera Clepsine, Nephelis,Aulostoma, Sanguisuga , Piscicola, and Branchiobdella arecharacterized, and Clepsine marginata, tessulata, complanata,hyalina, Carenm and bioculata, species that occur nearBerlin , are described at length, and to these besides is addedthe new species Clep. verrucata. The latter can be dis-tinguished from Clep. complanata only by the internal struc-ture. Clepsine verrucata possesses, for instance, “ appendicumventriculi paria 7, par ultimum inter appendicum intestinipar primum et secundum terminatum Clepsine complanata,on the contrary, “appendicum ventriculi paria 6, par ultimuminter appendicum intestini par secundum et tertium termi-natum.” In Clepsine complanata, Muller observed, beforethe expulsion of the ova, on both sides of the abdominal