SEA-FISHERIES LABORATORY. 145 



the pigmented epithelium over them is distinctly dis- 

 cernible) in the dermal lymph-spaces, held in place by 

 the surrounding tissue, but not embedded in it, and the}^ 

 can easily be removed with only a few lymphocytes, &c, 

 attached. They are quite absent from the somatic mus- 

 culature. On opening the body-cavity, numerous parasites 

 are seen in the gut-mesentery, usually close to, but not 



an idea of their appearance in the mesentery of one loop 

 of the intestine, from which it will be seen that, when 

 internal, the cysts are uniformly slightly smaller than 

 when beneath the skin. They are generally oval or 

 elliptical, and never exceed 1 mm. in diameter. 

 Unfortunately, I have, so far, not found any younger, or 

 different, stages, but it is most likely that the parasites, 

 when smaller, pass into a blood-capillary or lymph- 

 channel from the gut, and there grow and encyst (?), 

 since in section (fig. 3) they are surrounded by a space 

 (spa.). All the internal organs are quite free and normal, 

 and for this reason I should not say the hosts are harmed 

 to any dangerous extent. The two or three afflicted speci- 

 mens which I have so far seen certainly cannot be 

 described as " emaciated." 



Minute structure. Notwithstanding the size the 

 things grow to (up to 1-| mm. in diameter) each is, 

 undoubtedly, a single cell ; as to that I have not the 

 least doubt. There is no trace of cell- division, nor of 

 cell-nuclei in the ordinary sense, in it ; whatever a cyst 

 represents, it is, as a whole, unicellular. Fig. 3 is a sec- 

 tion, slightly magnified, through one in the mesentery, the 

 space around representing an enlarged capillary or a lymph- 

 channel, as already mentioned. This happened to be 

 more spherical than the internal ones usually are; it is 

 surrounded by a layer of amoebocytes, &c. (lym), rather 

 L 



