﻿On the Occurrence of a Supposed Australasian Hyclroicl. 83 



Thompson, D'Arcy W., 1879. New and Rare Hyd. Zooph. 

 from Australia and New Zealand, Ann. Mag. Nat. Hist. (5), 

 vol. iii. 



Explanation of Ir'LATE. 



Colonies of Sertularia elongata picked up in tlie North Sea (slightly reduced). 



The central thicker and whiter rod is the twig over which the hydro- 

 rhiza of the colonies ramify, the whiteness being due to an encrusting 

 polyzoon layer. 



/ 



VI. Studies on a Trypanosome found in the Alimentary 

 Canal of Pontobdella muricata. By Muriel Eobertson, 

 ., Carnegie Eesearch Scholar in the University of Glasgow. 

 [Plates IV.-VIL] 



(Read 17th December 1906.) 



In the leech, Pontohdella muricata, which is found parasitic 

 on skates, and also, I believe, though less frequently, on 

 anglers (Lophius), there is present a trypanosome. 



M. E. Brumpt is of the opinion that this trypanosome 

 forms part of the life-history of T. raice (C. B. Soc. Biologic, 

 t. Ix., 27th Jan. 1906, pp. 160-166), but he gives no details, 

 and has, as far as I am aware, published no figures. I am 

 inclined to support this view, in spite of the very marked 

 difference in size and appearance between the trypanosome 

 in the leech and T. raice (cf Figs. 1 and 2 with the remaining 

 figures), but am not yet in a position to make any definite 

 statement in the matter. I propose in the present paper to 

 place on record certain details regarding the part of the life- 

 history passed in the alimentary canal of the leech. I do 

 not claim that this is a complete account of all the phenomena 

 found in the leech, for although a very considerable number 

 of animals was investigated, I have had no opportunity of 

 carrying out experimental feeding. 



The material was obtained partly from the Zoological 

 Station at Xaples, and a few specimens were sent from the 

 stations at Plymouth and Millport. The great bulk of the 



