314 Proceedings of the Royal Physical Society. 



it will be observed tliat Duddingston Loch has as yet yielded 

 the greatest number of species, viz., 22, exclusive of a 

 Candona which differs somewhat from any previously 

 described ; it comes nearest Candona rostrata, Brady and 

 Norman, but is decidedly more tumid than that form, and 

 so for the present it is set aside as doubtful. 



While examining some specimens of this tumid form, 

 I noticed alongside one of the animals an object that I at 

 first thought might have some connection with the sexual 

 organs. I mounted the specimen with the object in situ and 

 sent it to Dr Brady, but he could not say what it was. 

 Possibly it is a parasite of some kind, and may, partly, be 



raia-site (?) observed in one of the tumid Candonce from Duddingston ; 



greatly enlarged. 



the cause of the more tumid form of the Candonce referred to. 

 It is obscurely rhomboidal in outline, the base is truncate 

 and deeply notched ; internally and springing from one side 

 of and a little above the base are six elongated, curved teeth, 

 having their lower part much broadened inwards, three 

 of them being curved inwards and three curved outwards. 

 My son suggests that it may be the cestocercal stage of a 

 species of Cestoda, whose ultimate development is reached in 

 some fresh-water fish, as the trout or stickleback tliat preys 

 on Entomostraca. 



Cyprois Jlava (Zaddach), from Duddingston Loch, is an 

 interesting species because of its very restricted distribution. 



