76 REPORT OF THE COMMISSIONER OP FISH AND FISHERIES. 



ENDOPLASM. 



Much more coarsely and more or less yellowisli granular, containing 

 numerous nuclei, fat-globules, and sometimes one or more vacuoles ; 

 also pigment. 



N'uclei. — First observed by Prof. Blitsclili ' in Myxidium UeherMlhnii^ 

 where their nuclear nature was shown both by their structure and by 

 their affinity for carmine; always very numerous, the smallest occur- 

 ring only in the youngest forms, strewn irregularly through the endo- 

 plasm. As in a number of species the nuclei have been observed to 

 originate by division, there is every reason to suppose that such origin 

 obtains throughout the snbclass^, and that the myxosporidium nuclei 

 are to be referred back to the nuclei of the sporoplasm. 



" Granules'''' and '■'■ globules.^'' — Many of the structures loosely termed 

 " granules" and "globules" by the older authors are really nuclei, and 

 this should be borne in mind in reading their descriptions, which have 

 sometimes been reproduced wathout change (see also pp. 209, 220). 



According to Biitschli (see page 285), these bodies are of a fatty 

 nature, as sbown by their complete solubility in alcohol. According 

 to several other authors, the hrematoidin crystals are found within 

 globules whose fatty nature was presumed from the same reaction. 

 Thelohan, however (see below), while admitting the solvent action 

 of alcohol upon certain chromatophorous globules observed by him 

 in Chloromyxum leydigii and in Myxidium Ucherlmhnii, denies their fatty 

 nature, as osmic acid is without action upon them. 



Fat-glohules. — Feebly glittering; size variable; always j^resent except 

 in very young individuals ; especially frequent in Myxidium UeherMlhnii. 



Vacuoles. — Sometimes one or more; number, position, and presence 

 inconstant; apparently always nonpulsating. 



Pigment. — Although it has heretofore seemed probable*^ that all pig- 

 ment occurring in the Myxosporidia was of extraneous origin, it would 

 appear now, from Thelohan's recent observations, as though perhai^s 

 the presence of proper pigment must be admitted. This observer says :^ 



In many myxosporidia which live in the free state in the natural cavities one 

 finds the endoplasra riddled with strongly colored globules whose tint varies from 

 golden yellow to brown. Very numerous in Myxidium, they give to the intei-nal 

 face of the pike's bladder a characteristic yellow tint; they also exist in Chloro- 

 myxum leydigii (Mingaz.). As these elements do not resist the action of alcohol or 

 that of the essential oils, one finds no trace of them in sections; they are not fatty, 

 as osmic acid is without action upon them. 



Chloromyxum fluviatile also contains similar structures. 



1 Ztschr. f. wiss. Zool., 1881, xxxv, pp. 632-633; Bronn's Thier-Reich, 1882, i, pp. 

 594-595. Biitschli (1882) was the first to suggest the generality in the Myxosporidia 

 of the multinucleate condition. Lankester (see p. 73, foot note 1) took the same view. 



2 This is also Thdlohan's opinion (Bull. Soc. philomat. Paris, 1892, iv, p. 169). 



3 As Biitschli remarked iu 1881 (Ztschr. f. wiss. Zool., xxxv, pp. 642, 649). Cf. also 

 Pigment in index. 



