90 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



and no evidence in favor of Mingazzini's supposition that the capsules 

 repvosent the embryos, the fihinients functioninji- as flaiiella\^ 



On the contrary everything that we know about the Myxosporidia 

 favors the view that the embryo is not the capsule but the sporoplasm, 

 the presence in it of nuclei, of a vacuole, and of amoeboid movements 

 being quite conclusive. The most probable sn])position in relation to 

 the capsules is that they are accessory and temporary structures whose 

 function is to secure attachment and perliaps a certain amount of 

 motion, for the fultilhnent of both of which objects they seem very 

 well adapted. And it maybe noted in passing that nemsltocystoid 

 bodies are known wliich function for attachment, as well as those which 

 function for stinging, etc.^ 



Before discussing the mode of action of the filaments, a few words 

 may advantageously be devoted to the relative functions of the spore 

 and myxosporidium stages. 



(1) Bifipcrsal i,s absolutclij necessary to the species: This dispersal can 

 take place only by the actual separation of myxosporidian individuals 

 from one host and their migration to another, unless we adopt one of 

 two very improbable sui)p()sitions, viz, either that they attach them- 

 selves to the eggs of the host and await their development or that they 

 develop in an intermediate host which feeds upon the fish.^ 



(2) The spore is the means by ichich such dispersal is effected:* Thus 

 Lieberkiihu^ saw some cysts "lost" and others opened, their contents 

 escaping into the water. Also Ludwig and Kailliet (p. 22») have 

 observed the rupture of cysts in situ with escape of their contents. 

 Thelohan*' has seen the same occur with Glugea anomala; and in Myx- 

 obolus ellipsoides he saw cysts shell out entire and burst." 



' Mingazzini's description given above implies very strongly this idea as to the 

 fuuction of the filaments, nevertheless he does not distinctly so state. Compare here 

 Lieberkiihn's statement (Bull. Acad. Roy. Belg., 1854, xxi, pt. 2, p. 21) that the 

 capsiiles, when extruded with the sporoplasm from the spore, show not the slightest 

 trace of movement. 



'^ In the body epithelium of the Ctenophora we iind peculiar adhesive cells with 

 uneven and sticky surfaces. Their bases are prolonged into spirally coiled con- 

 tractile filaments. — (Arnold Lang's Text Book of Comparative Anatomy, London, 

 1891, pt. 1, p.82.) 



'The latter mode of change of host, though improbable, is not inconceivable. 

 Still, everything seems to point toward the view that the whole life cycle from the 

 attached spore in one generation to the liberated spore in the next, takes place in the 

 same host. 



* The only place where this view is distinctly stated is the following (Mile. 

 Leclercq, 1890, Bull. Soc. Belg. de Microsc, xvi, p. 101): 



"On account of the presence of organs compared to nematocysts, lut which seem 

 rather elaters, one can believe that the spore is the disseminating form of the para- 

 site, and that it can lead for some time a free life in the water." [Italics my own 

 for errors.] Here we again see the unfortunate results of the dual signification Ox 

 the term " filament." 



^Muller's Archiv., 1854, p. 356. 



e Compt. Rend, hebdom. Soc. Biol. Paris, 1892, iv, pp. 82-4. 



' Annal. de Microgr., 1890, ii. pp. 203-4. The observation was upon a spore habi- 

 tant on the tench iMyxobolua dU^soidest). 



