THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 85 



by tlie occurrence of both in the same species under the influence of 

 sulphuric acid. The other reagents which tend to produce filament- 

 extrusion are caustic alkalies, hydrochloric and nitric acids, ether, 

 glycerin, boiling water, mechanical x)ressure (e. g., the rolling of a 

 mass of spores in an insufficiency of fluid, under the cover-glass), etc. 

 As noted by Eiitschli,^ the extrusion in the latter case is apt to be more 

 or less abnormal. 



Concerning filament-extrusion in preserved material, Thelohan^ 

 says: 



After the actioii of alcohol upon the spores the filament remains in the capsule 

 and it becomes impossible to make it go out. 



While not usual, extrusion does sometimes occur with alcoholic speci- 

 mens, a certain (rather small) proportion of the spores emitting their 

 filaments under the action both of sulj)huric acid and of iodine water. 

 In my experience the filaments appear usually not to have much affin- 

 ity for stains; the capsule where stained, always shows a markedly 

 lighter center. Kolesnikoff, however, found them to stain in Myxoholus 

 JcolesniJcovi. 



HOMOLOGY AND FUNCTION. 



The capsules were first observed by Miiller (see p. 241), who consid- 

 ered them the embryos. 

 In 1852 Leuckart ^ regarded these structures as fat globules. He says : 



Also, they [the sjiores] contain s<>me plain granules of a fatty quality, which are 

 distinguished through their eonstant location in one or both poles. 



In 18G3 Balbiani * discovered the filament and its capability of extru- 

 sion. Regarding the spore as an adult cryptogam, he assigned to the 

 filament the role of an antherozoid. 



In 1875 Schneider^ remarked that — 



As regards a resemblance between the falciform corpuscles and the polar organs of 

 the psorosperms of fishes, it is impossible for me to find it. * * * The falciform 

 corpuscles are not such sacks occupied by a slender filament rolled into a spiral. 



Commenting upon Balbiani's views, Leuckart says:^ 



The signification of the elements is unknown, but it may be safely admitted that 

 Balbiani's view, which sees therein an antherozoid, is without foundation. Perhaps 

 it is to be regarded as an attachment apparatus. 



He further remarks that a comparison of the capsules with the falci- 

 form corpnscles is excluded by Lieberkiihn's and Balbiani's observations 

 of the exit and amoeboid movement of the sporoplasm. 



iZtschr. f. wiss. Zool., 1881, xxxv, p. 635; see Myxoholus miilleri, p. 219. 



^Annal. de Microgr., 1890, il, p. 207, 



3 Archiv. f. physiol. Heilkde, xi, pp. 434-5. 



■• Conqit. Rend. Acad. Sci. Paris, lvii, p. 159. This discovery has since been con- 

 firmed by numerous observers. 



* Archiv. de Zool. Exper., Paris, iv, pp. ,548-9. I have not seen a distinctly asserted 

 comparison between the capsules and the falciform corpuscles to which this could 

 refer, but such a comparison is implied by Leiickart's parallelism of Myxidium ( f) 

 sp. 102 (Archiv. f. physiol. Heilkde, 1852, xi, fig. 21 b) with the'spore from the testicle 

 of Lumbricus. 



6 Die Parasiten des Menschen, 1879, 2 ed., p. 247. 



