ELOOD-PAKASITES OF FISHES OCCUERlNCr AT KOVIGXO. 123 



and more or less bluntly rounded. In the slender forms, on 

 the other haud, one half of the body is usually narrower than 

 the otlier and tapers towards its extremity, the opposite end 

 being bluntly rounded. The more pointed end may be curved 

 or partially bent up on itself (figs. 18, 21), this being most 

 likely due to limitations of space; the drawn-out corpuscle is 

 apparently incapable of being stretched to the full extent of 

 the length of these forms. (We have not seen any phases in 

 this parasite, it should be said, indicating- the development of 

 a definite U-form such as occurs in many hsemogregarines.) 

 The average size of the slender type is 12 ^u by 2-1 ju; and 

 individuals np to 14 /x long have been observed, the breadth in 

 this case being 2*2 ju. The stout forms average 10*6 ju by 3-4 /u, 

 and their extreme size is about 11 /t by 3-5 /x. The size of the 

 nucleus differs greatly in the two cases, and this is a constant 

 feature. In Giemsa smears the nucleus of the slender type 

 averages 2*6 /z by 1-7 jU and that of the wide type 4-8 ju by 

 2'9 // ; in iron-hgematoxylin preparations the former is 2"5 ju 

 by 1*4 fx and the latter 4 ju by 2-2 jn. In the slender forms the 

 nucleus is always in the narrower, tapering half. 



The structure of the nucleus appears practically the same 

 in both the stout and slender individuals ; it agrees closely 

 also with the structure of the nucleus in the small forms. 

 The cytoplasm of these large forms, however, differs greatly 

 in character from that of the small parasites to judge from the 

 effect produced by the Giemsa stain. The difference is 

 especially noticeable in the case of the slender forms. Here 

 the broader half of the body (not that in which the nucleus is 

 situated) is nearly always more or less completely filled with 

 some substance which stains red, and which may indeed 

 appear at times almost as deeply and intensely stained as the 

 nucleus (cf . figs. 19, 21). Often the colour increases in depth 

 regularly towards the broad end, as if the substance which 

 attracts the stain were most concentrated in that region of the 

 body (fig. 18). From the effect produced by the Giemsa 

 stain it would seem as if the mass were of a finely granular 

 character and consisted of chromatoid material. Some of the 



