THE MYXOSPORIDJA,. OR PSOROSPKRMS OF FISHES. 285 



of dark, longitudinal, ectoplasmic laminae separated by clear, somewhat 

 reddish, apparently semifluid interlaminse. Not iufrequeutly there exists 

 a similar clear reddish boundary layerbetween ectoplasm and endoplasm 

 (Biitschli). 



Endoplasm consisting of colorless or yellowisli myxoplasm, usually 

 tinted reddish to reddish-brown (see Hcematoidin below); distinguished 

 from the ectoplasm by its color and by the presence of granules, globules, 

 numerous small nuclei, vacuoles and inclusions (notably hoematoidin 

 crystals). Granules minute, arranged without order. Globules num- 

 erous, irregularly scattered; in all probability fatty, being soluble in 

 alcohol ; ^ containing ha^niatoidin crystals. The older writers also 

 include the nuclei under the term globules. 



Nuclei very numerous, small, with a dark surrounding membrane, 

 granular contents, nucleolus and radiating fibrilhe (Biitschli). Pfeifier 

 remarks ^ that these are to be referred back to the original single 

 nucleus of the young myxosporidium. 



Vacuoles (apparently nonpulsating; indefinite as regards number 

 and position), are sometimes seen in forms with few granules. 



Hsematoidin crystals: These were first observed by Lieberkiihn.^ 

 They were subsequently noted by Biitschli, * who rightly remarked 

 that they must be derived from the blood of the host; i. e., tliat they 

 are of extramj^xosporidian origin. They occur in the fat globules, and 

 are found free in the protoplasm only after solution of these globules by 

 alcohol. They can be found from the smallest beginnings up to a more 

 conspicuous size, the fat globules then forming a proportionally slight 

 covering for them (Biitschli). 



Pfeiffer * describes and figures a red blood corpuscle as included 

 within the endoplasm. This he regards as the source of the hcema- 

 toidin crystals. He asserts that they are constantly present and that 

 they occur free or within the fat-globules. He adds that if the myxo- 

 sporidium has amoeboidly surrounded these blood corpuscles and now 

 consumes them, then in spite of the structure of the spores the Myxo- 

 sporidia can no longer be regarded as Gregariues. 



Pseudopodia of 2 kinds: (1) Blunt, obtusely rounded, usually 

 formed of ectoplasm alone, endoplasm taking part in formation only 

 where the body as a whole forks. (2) Fine, hair-like or bristle-like, 

 usually rigid, frequently branched, comparable to similar processes of 

 many amcebse, frequently covering whole surface, not rarely, however, 

 limited to a certain region of same (e. g., the end, as in certain amoebse) ; 



1 Biitschli, Bronn's Tliier-Reich, 1882, i, p. 594. 



2 Die Protozoen als Kraaklieitserreger, 1890, 1 ed., p. 44. 

 ^Miiller's Arcliiv., 1854, p. 350; see also next footnote. 



* Ztschr. f. wiss. Zool., 1881, xxxv, p. 642; Biouu's Thier-Keicb, 1882, i, p. 594. 

 •Biitschli credits their discovery to Lieberkiihn and Meissner. I infer from Lieber- 

 kiihn's statement, that Meissner's results were communicated to him orally but were 

 not published. 



6 Die Protozoen als Krankheitserreger, 1890, led., p.4G; ih., 1892, 2 ed., pp.17, 132. 



