434 



6. Brief notes on two Myxosporidian organisms (Pleistophora hippo- 

 glossoideos, n. sp. and Myxidium mackiei n. sp.). 



By W. Cecil Bosanquet. 



(From Professor E. A. Minchins Laboratory of Protozoology , Lister Institute of 



Preventive Medicine, London, S. W.) 



(With 13 figures.) 



eingeg. 3. Januar 1910. 



The material on which the following brief notes are based was 

 given me for examination by Dr. H. M. "Woodcock, to whom my best 

 thanks are due for this and for his assistance and advice throughout the 

 investigation. 



1. Pleistophora hippoglossoideos n. sp. 

 The material in this instance consisted in three small portions of 

 tissue taken from the fin-muscles of the flat-fish, Hippoglossoides Uman- 

 doides. It had been hardened in alcohol and was already embedded in 

 paraffin. On cutting sections of these blocks, there were seen small 

 whitish nodules lying in the substance of the muscular tissue. The 

 nodules were round or oval in shape, and from 1 to 2 mm. in diameter. 



Fig. 1, 



Fiff. 2. 



Fig. 1. Spores (above) and Sporoblasts (below) oi Pleistophora hippoglossoideos. 

 Fig. 2. Spores of PI. hippoglossoideos, X 2000. 



The sections were stained with iron-haematoxylin, with Delafield's 

 haematoxylin, and with thionine, some being counter-stained with eosine 

 and others with orange. 



Microscopical examination showed the nodules to be made up of a 

 honeycombed mass of small cysts, most of which contained ripe spores 

 (Fig. 1, upper part). The cysts lay in a small amount of structureless 

 or fibrillated reticulum, apparently derived from the host, among which 

 remains of muscle-fibres were here and there visible. A slight degree 

 of cellular infiltration was seen at the edge of the nodules, but the 

 muscle-fibres in the neighbourhood seemed normal and unaffected. The 

 individual C3^sts measured some 20 to 25 /< in diameter. 



The spores were very minute, measuring about 3^2 /' iii length by 



