90 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



and no evidence in fjivor of Mingazzini's supposition that tlie capsules 

 represent the embryos, the filaments functioning as flagellai.^ 



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 supposition in relation to 

 the capsules is that they are accessory and temporary structures whose 

 function is to secure attachment and perhaps a certain amount of 

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

 well adapted. And it may be noted in passing that nematocystoid 

 bodies are known which 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) Dispersal is absolutely 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 suppositions, viz, either that they attach them- 

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

 develoj) in an intermediate host which feeds ujion the fish.^ 



(2) The spore is the ineans by which such dispersal is effected:^ Thus 

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

 escaping into the water. Also Ludwig and Railliet (p. 228) 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- 

 obolns ellipsoides he saw cysts shell out entire and burst.^ 



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

 function 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 

 capsules, when extruded with the sporoplasm from the sjiore, show not the slightest 

 trace of movement. 



2 In the body epithelium of the Ctenophora we find 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.) 



3 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, iut 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 oi 

 the term "filament." 



6Miiller'8 Archiv., 1854, p. 356. 



6 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 iMyxoholus ellipsoides?). 



