Report on Diseases and Abnormalities in Fishes. 5 



nucleus (or vacuole) was made out in the larva shown in fig. 15. 

 The largest larva in fig. 4 measured *12 mm. in length. The tubes 

 in which the larvae are situated communicate with one another. In 

 some cases the termination of the tube could not be clearly made out, 

 c.<j., figs. 20 and 176. The ovum-like body is, I think, the elongated 

 larva encysted. In fig. 35 the larva appeared to be giving off a bud, 

 while what looked like a little detached bud was seen at ' a.' No 

 movement was detected in any of the larvae. The encysted larva? are 

 opaque, and are enclosed in a thin wall, e.g., op., fig. 20, but 

 translucent capsules having a thick investment are present (fig. 27, and 

 tr., fig. 29). In the latter case the contents of the capsule (tr.) seem to 

 have been lost. I think this thick-walled translucent capsule is a 

 later stage of the encysted larva ; it is larger in some cases and 

 smaller in others than the encysted larva. It will probably develop 

 into the condition shown in fig. 36, and further into the " columnar 

 body " to be described below. 



Two of the encj^sted larvae were tinted with green colour. The 

 two cells in fig. 28 were in the muscles apart from the cyst. They 

 were smaller than the encysted larva ; they contained round corpuscles. 

 At a little distance away from the main cyst little green bodies were 

 observed. They were bundles of green spore-like corpuscles. A 

 capsule was attached to the green body. 



In a second stage of the cyst the wandering larvae are seen to have 

 pushed their ways in every direction out among the muscle fibres. 

 Fig. 5 represents such a cyst. Under the dissecting lens the encj^sted 

 larvae (a.) are seen surrounding the cyst. If the cyst is dissected out 

 from the muscles the tubes break off, leaving the larvae in their 

 places. The cyst measured l'l mm. in length in the run of the 

 muscles. Fig. 22 shows a group of three larvae. The largest 

 measured "07 mm. in length. The larva, even when away from the 

 cyst, is covered with the thicker connective tissue. 



Some of the cysts show in addition columnar bodies (col., figs. 5, 11, 

 179). The columns are not muscle fibres. They are somewhat 

 translucent, colourless, and thejr are crossed by wavy lines. In some 

 cases the columns were somewhat dried up, e.g., fig. 16, but they are 

 bathed in a sticky plasma. When the column was teazed a powdery 

 material was obtained in addition to parts of the parasite. Muscle 

 fibres are bound up with the columns. I did not make out any ova 

 or spores in the columns. The column would seem to be the final stage 

 of the parasite. 



A small oval-shaped body, '2 mm. in length, separated from a cyst 

 by a little distance, is evidently the beginning of a column (fig. 178). 

 Fig. 6 represents the section of a cyst from the same fish. The cyst 

 measured, from x to y, 1*5 mm. The caenosarc of the parasite is 

 shown dark. Some of the chambers are empty. A wandering larva 

 is shown at /. a. Various columnar bodies (col.) are present. Fig. 

 36 shows what appears to be an early stage in the formation of the 

 column. The largest of these columns in fig. 179 was 1*9 mm. long 

 and "25 mm. wide. The columns maj 7 " be moulded in part by the 

 muscle fibres. 



A noteworthy fact is the extensive infection of the fish. This 

 indicates that infection probably takes place through the blood 

 system. The parasite does not feed on the muscles ; it derives its 



