HELEN L. M. PIXELL GOODRICH 



17 



V 



THE SPORE or THELOHANIA 



Helen L. m. Pixell GOODRICH 



D. Se. Lond. 



Reçu le 23 février 1920. 



A prawn, Leander {Palaemon) serratus, which I observed in the acqua- 

 rium tanks at Plymouth last January, had opaque white muscles and 

 seemed obviously infected with Thelohania octospora as described by 

 Henneguy and Thélohan (1888, 1892, 1894). On teasing the infected 

 muscle however and examining the parasite in sea water great was my 

 astonishment to find that each of the spores was provided with three 

 long tails (figs i et ii). 

 Thèse tails are délicate pro- 

 longations of the epispore 

 as found in many Haplos- 

 poridia. Inside the sporo- 

 cyst thej' are curled round 

 the spores and take up 

 a considérable amount of 

 space. This fact doubtless 

 accounts for the interesting 

 observation recorded by 

 Henneguy and Thélohan 



(1892, p. 630), that the réfringent spores only occupy part of the cyst in 

 Th. octospora. When the sporocyst is only ruptured at one spot a tuft 

 of tails from the enclosed 8 spores often projects through the fissure. 



The sporocysts are about 8 ;j. in diameter and most of the fresh spores 

 are only 3 jj. long according to my measurement, though occasionally 

 maeroscopores up to 5 or 6 [j. are to be found. The tails are about 20 [x 



Notes et Kevul. — T. .ît».^ — X" i. h. 



FlO. I. Spore of Thelohania drawn from thr living at an approxi- 

 mate maftiiification of 2.000, showin<r tlio three tails. 



