222 Proceedings of the Royal Physical Society. 



In the Forth area few of the forms have yet been seen — 

 one example found near Penicuik had ten spines, all directed 

 backward ; another had eight spines. 



Genus Callidina. 



Animals with three toes, or a perforate disc formed by 

 a union of the toes, oviparous, eyes present or absent. The 

 very few viviparous species formerly included in this genus 

 have been transferred to Piotifer or Philodina, with which 

 their real affinities lay. 



Animals belonging truly to Callidina have been found 

 exceptionally to contain living young. I believe, however, 

 that in those instances what has happened is that the egg 

 has hatched within the parent, and that the mode of repro- 

 duction is really invariable in each species. I believe, 

 further, that the mode of reproduction is generic — related 

 animals have the same mode. The exceptions are so few 

 as to prove the rule. 



As in Philodina, several natural groups can be recognised. 



A. Food moulded into jpellets. 



This is by far the largest and most important natural 

 group found within the order. It is possibly of more than 

 generic value, as is suggested by the occurrence within its 

 limits of every condition in relation to eye-spots found in the 

 whole order, viz., eyes in rostrum, eyes on brain, and no eyes. 



C. hexodonta (Bergendal), (1), (11). 



Otterston, near Aberdour, March ; Bavelaw Moss ; top of 

 East Cairn Hill, Pentlands, September. 



C. rceperi (Milne), (10). 



A parasite or commensal on Sphagnum, Bavelaw Moss, 

 February. 



C, elegans, Ehr. (6). 



Blair Drummond, near Doune, April. 



