176 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



6. Genus et sp. incert. PI. 4, figs. 2-8; pi. 5, figs. 1-11. 



Pilzsporeu of Ct/dops, Clans, 1863, Die freilebemlen Copepoden, Leipzig, p. 

 87; Myxosporidia'? of Cyclops, of Diapt. cceriileiis and of Diapt. richardi, 

 Schmeil, Beifriige z. Keuntn. d. freilftbeuden Copepoden Deutschlands, 

 Ztschr. f. Naturwiss. Halle, 1891, lxiv, pp. 19-21; Eutoparasitische 

 Schlliuche der Cyclopiden SchewiakofF, Ueber eiuige ekto-, and euto- 

 parasitische Protozoen der Cyclopiden, Bull. Soc. Imp. Nat. Moscow, 

 1893, pp. 2, 15-26, pi. 1, figs. 17-34. 



Clans says : 



The bodies formerly ^ designated by me " spores of fungi," with which I have many 

 times found the bodj'-cavity of Cyclops entirely tilled, I have unfortunately not been 

 able to observe again in later times. From the earlier period, sufficient notes on 

 these bodies unfortunately are lacking, so that I am compelled to leave undeter- 

 mined their nature and their relation to Parhistophytonovatum, so full of significance 

 through the disease of the silk- worm. 



To his quotation of part of the above Schmeil (p. 21, footnote 1) 

 adds : 



" T7(e organisms observed by me are, hoivever, certainly not S2}ores of fungi" [italics his 

 own]. 



Schmeil further says (abstract) : 



I have observed another parasite in nearly all the Cyclops of the Halle 

 [Page 19] region, further in the specimous seen of Diapt. cccruleus Fisch. and D. 

 richardi Schmeil. 



As this parasite is relatively very frequent — though absolutely (stdndig) 

 [Page 20] rare — one soon learns to tell the affected animals with the naked eye by 

 their striking gray color. Their movements are unaffected. Microscopic 

 examination shows individual parts of the body strikingly dark (in Cyclopids and 

 D. richardi Schm., black; D. coeruleiis Fisch., dark brown); often the whole thorax, 

 the abdomen, and even the tail, the first antenme, and natatory feet are either 

 entirely or partly filled by this dark mass. On closer examination this dark color 

 is seen to be due to an innumerable host of small fusiform or crescentic corpuscles, 

 whose form (plainly perceived by pressure-rupture of the copepod shell) places 

 them as psorosperm-like bodies. From Schmeil's description and drawings, Biitschli 

 considered tlienx Myxosporidia. Size very variable; besides very small corpuscles, 

 one meets with larger ones 3 or 4 times the smallest, but the sizes of all those 

 occurring in the same individual are always nearly equal. These corpuscles appear 

 to possess a firm membrane, immediately within which a clear zone is situated. No 

 differentiation of contents could be observed. Water and glycerin do not alter the 

 form. 



Origin of these corpuscles unknown; repeated attempts to infect 

 [Page 21] healthy animals failed. Multii>lication by division seems proven by the 

 occurrence of two or several corpuscles lying close together, often in con- 

 tact lengthwise; often, however, with their blunt poles surrounded by a common 

 membrane. Therefore, in case the explanation generally given is correct, a double 

 division in the transverse and longitudinal axes appears to take place. 



On account of the lack of infected animals it is exceedingly difficult to reach safe 

 conclusions concerning these conditions. 



Such was the state of the subject when Schewiakoff began his investi- 

 gations. The following are his results: 



This condition has been observed at all seasons, first on Cyclops strenuus Fisch. 

 taken from under the ice of a pool (clay ditch near Schlettau). 



' Place not stated; or whether published. 



