The Bdelloid Roti/era of the Forth Area. 221 



has only a single series of dorsal spines, crossing the central 

 segments. The other has an additional shorter row farther 

 back. 



Both occurred together in wet moss from Torduff ; the first 

 at Gullane Links, November, very abundant ; also at Winch- 

 burgh in December, and on the Ochils in June. 



P. alpium, Ehr. (3). 



On Elodea from ditch at Winchburgh, December. 



A very common animal all over Scotland. Its occurrence 

 only on one occasion in the course of a year's work in the 

 Forth area is therefore somewhat surprising. 



C. Vivvparous ; eyes present or absent. 



The only two species belonging to this section of the 

 genus, which have been found in the district, normally 

 possess eye-spots. Blind forms of both are occasionally 

 found, and a third species, not yet found in the area 

 (P. spinosa), is normally blind. 



P. macrostyla, Ehr. 



Generally distributed and very common. 



Duddingston ; Nether Habbie's Howe ; East Cairn Hill, 

 Pentlands, September; Loch Leven, April ; Winchburgh, etc. 

 Var. tubercidata in the same localities, and also from Aber- 

 foyle, December. 



P. aculeata, Ehr.? 



It is somewhat doubtful if the spiny Philodina, so common 

 in Scotland, is Ehrenberg's species. That is figured as having 

 about twenty-seven spines, but the greatest number which I 

 have seen is twelve. If it is the same it is extremely 

 variable, and has puzzled authors accordingly, almost every 

 naturalist who has noticed it giving a different account of 

 it. In my experience, the spines have always been in pairs, 

 and vary from four to twelve in number. Mr Bryce has 

 seen a form with only two knobs, but he is disposed to regard 

 this as belonging to P. macrostyla. 



