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THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 273 
92. Chloromyxum (Sphzrospora) dujardini Thélohan, 1892. Pl. 40, figs. 4-7. 
Cyprinus 
Cyprinus| eryth- 
rutilus, | roph- 
“psoro- |thalmus, dujardini. Date. Authority; reference. 
sperms’’ | ‘‘psoro- 
of. sperms” 
of. 
x Mites eaccaa- soe sees 1841 | Miiller, Miiller’s Arch., pp. 481, 486, pl. 16, 
fig. 4b, c. 
x Debye esos boeeeeets 1843 Miiiler, | Rayer’s Archiv. Méd. Comp., I, p. 
226, pl. 9, fig. 40, ¢. 
we) WAS So Ree Re aeeeiasorsac 1843 Rayer, Rayer’s Archiv. Méd. Comp., I, p. 
(pars.) 269. 
BE oe Sere arse 1845 | Dujardin, Hist. Nat. des Helminthes, p. 644, 
pl. 12, fig. 12 N,, 12 No, 
x SES) [a aoe aie te 1853 | Robin, Hist. Nat. Végét. Par., p. 299, pl. 14, 
(pars.) a eations 6. 
gma ara on raw ell aia’ ayciniciajalare mimo e 1882 Biitsehli, Bronn’s Thier-Reich., I, pl. 38, fig. 5. 
Myxosoma et} 1892 Thélohan, Bull. Soe. philom: it. Paris, IV, p. 
Mixosoma .-.! 175. 
Chloromyxum| 1893 | Gurley, Bull. U. 8. Fish. Com., XI, p. 419. 
Myxosoma ..-| 1893 | Braun, Centralbl. Bakt. u. Parasiteukde, 
| esse too: 
adonconeé=|SOeseo sec Chloromyxum | 1894 | Braun, Centralbl. Bakt. u. Parasitenkde, 
| | | XV, p. 87 
Synonymy.—The first 6 references in the table, except those to Dujar- 
din and to Biitschli, represent the same form, the later being mere copies 
of Miiller. The fusion of the form observed by Dujardin with that ob- 
served by Miiller is on the authority of Théelohan, who states (letter to 
the author, 1893) that he has observed his Myxosoma dujardini upon both 
Leuciscus rutilus and L. erythrophthalmus, and that he believes that 
Miiller’s and Dujardin’s figures represent the same species. Biitschli’s 
form is also probably referable here; size of the last, 0-46 mm. 
Concerning the form observed by hints in Leuciscus r til us, Miiller says: 
Once there was found on the pseuclobranchias ( Nebenkiemen) a mass of small yellow 
cysts. The size of this mass was 4 lines. This time all the cysts contained elongate 
capsules [spores] with pointed anterior and bluntly rounded posterior ends (fig. 40). 
On the flat border the convex surfaces were exactly equal and the 2 diverging vesi- 
cles were attached interiorly at their points. 
Thus this form was never found coexisting in the same cyst with 
Myzxobolus cycloides. Considering the great frequency of occurrence of 
the latter species such coexistence would be expected if they were 
merely different forms of one species. Their persistent nonassociation 
thus strongly reinforces the argument in favor of their specific distinct- 
ness drawn from their different characters. 
Cyst not described. 
Myxosporidium.—Spores imneddeds in and held together by an almost 
diaphanous, ramified, glutinous mass, 1°25 to J:50 mm. long, decompos- 
able by water, analogous to the amcebe, apparently destitute of an 
envelope (Dujardin). 
Spore.—Oval, pointed anteriorly, broadly rounded posteriorly, length, 
10 to 12 yu (0-0051’’’ to 0:0054/’’); breadth, 7 yz (0:0034/’’) untailed; cap- 
sules 2, of equal size (Miiller). 
Habitat.—Encysted in the pseudobranchize of Leuciscus rutilus from 
German rivers; branchial lamelle of Leuciscus (Scardinius) erythroph 
thalmus from the Vilaine, at Rennes, France, 
F c——18§ | 
