September, 1900.] 215 



THK IRISH SPPXIKS OF I,AND PI.ANARIANS. 



BY R. F. SCHARPF, PH.D., M.R.I. A. 



Thk recent publication of Prof, von Graff's magnificent 

 monograph on the assemblage of worms known as " Land 

 Planarians," gives me an opportunity of reviewing this group 

 as far as we are concerned in Ireland. Anyone who wishes 

 to obtain additional information on the subject of these 

 remarkable flatworms can see the original (" Monographic der 

 Turbellarien," part ii., 1899) in the National Library of 

 Ireland. Until recent years a few species only of land 

 planarians had been discovered, though many marine and 

 freshwater species were known to science. Prof, von Graff 

 now makes known to us some hundreds of species of land 

 planarians, of which however onl}' seven have hitherto been 

 found in Europe. Most of the others are confined to the 

 warm and moist tropical forests. In shape they are much 

 flattened from above downw^ard, so that some of them are leaf- 

 like ; others more elongated, might be described as ribbon - 

 like, and a few are more or less cylindrical. A distinct head 

 is never recognisable, but there is always something to 

 mark off the anterior from the posterior end. Minute eyes 

 are nearly alw^ays present, and sometimes the anterior end has 

 a different shape from the posterior. The mouth is usually 

 placed some distance back on the ventral surface. 



Only seven species of land planarians have been recorded 

 as European, but I was so fortunate as to discover another 

 in the Pyrenees last autumn, which has lately been described 

 in the Proceedings of the Lhinean Society. Probably all the 

 land planarians are carnivorous. Their presence need not 

 therefore be dreaded by owners of greenhouses in which 

 they may make their appearance. On account of their 

 underground habits, these worms have only a very restricted 

 range, and their natural means of dispersal must be exceed- 

 ingly limited. To students of the geographical distribution 

 of animals they are therefore of particular interest. Now as 

 regards the Irish species, there are only three, one of 

 w^hich moreover is probably introduced, viz. ; — Placocephalus 

 {Bipaliuvi) Kewensis. 



