224 J. MURRAY ON PHILODINA macrostyla, ehr., 



timid, and never showed itself to advantage, yet with the diagnosis 

 and figure he gives the animal may be confidently identified. 



To the preceding description I have little to add, except that 

 in general form and details of structure this species is precisely 

 like P. aculeata and P. macrostyla. 



It is distinguished solely by the peculiar spines. There appear 

 to be ordinarily no eye-spots, but so few examples have been 

 seen that we cannot yet be certain that this is the normal 

 condition. Individuals without eye-spots are quite frequent in 

 the other two species. 



Even without seeing it feed or observing the toes, Mr. Bryce 

 remarked the resemblance to Philodina. 



In 1893 Bryce (2) announced that he had found two other 

 examples of P. spinosa, and that the dental formula was 3/2. 



This corresponds curiously with the dental formula ascribed by 

 Burn (3) and Western (19) to P. macrostyla. 



The probability is that the number of teeth varies ; but 3/3 

 appears to be the commonest formula for P. aculeata and 

 P. macrostyla. 



P. spinosa is not sufficiently known, as only a few examples 

 have yet been seen. 



Too much importance must not be put upon the form ascribed 

 to the spurs in the preceding description. This appears to have 

 been an individual peculiarity, and I found the spurs very much 

 as in the other species. 



The form of the head when feeding is that common to the 

 group, and the toes are four in number. 



Among Sphagnum, bog near Fort Augustus, 1903. 



I am not aware that any one else has seen the species 

 since its original discovery, so that it appears to be rare. 



Janson (13), in his monographic study of the family, includes 

 Callldina spinosa, but without having himself seen it. 



Literature. 



This list includes only works referred to in the text. Cir- 

 cumstances render it impossible to attempt a more complete 

 bibliography. 



