THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 135 
DESCRIPTION OF GENERA AND SPECIES. 
Tabular Key. 
The following tabular key includes all the species, which can by any 
reasonable possibility be construed as myxosporidian, with their prin- 
cipal characters plotted out. The order of arrangement is a trifle more 
artificial than that found in the text. 
Descriptions of the following species are omitted, as I believe there 
is no rational chance of their being Mywxosporidia: 
Psorospermium heeckelit Hilgendorff, 1883. 
(Parasite of Astacus jluviatilis, Hiickel, 1855, De telis quibusdam Astaci fluvi- 
atilis, Inaug. Dissert. Friedr. Wilhelm. Univ. Berlin, p. 42, pl. 2, fig. 25A-C; 
ib. Hiickel, 1857, Ueber d. Gewebe d. Flusskrebses, Miiller’s Archiv., pp. 561-2, 
pl. 19, fig. 25A-C; ib., Grobben, 1878, Beitriige z. Kenntn. d. miinnl. Gesch- 
lechtsorg. d. Dekapoden; not seen. 
Psorospermium heckelii, Bericht d. Gesellsch. Naturf. Freunde Berlin, pp. 179- 
181 (not seen); ib., Zacharias, 1888, Ueber Psorospermium hdckelii, Zoolog. 
Anzeiger, XI, pp. 49-51 (abstr. Journ. Roy. Micr. Soc. London, 1888, vii, p. 
240); ib., Wierzejski, Kleine Beitriige z. Kenntn. d. Psorospermium hdckelii, 
Zoolog. Anzeiger, XI, pp. 230-231 (abstr. Jour. Roy. Micr. Soc. London, 
1888, VII, p. 598). 
This form and the next have never been definitely referred to the 
Myxosporidia, but Prof. Linton’s bibliography of the “Psorospermie” 
includes the articles containing them. They have no connection with 
the Myxosporidia, 
Psorospermium lucernarie Vallentin, 1888. 
Zoolog. Anzeiger, XI, pp. 622-623; abstr. Journ. Roy. Micr. Soc. London, 
1889, pp. 75-76. 
See note on preceding. 
Pfeiffer? states that Myxosporidia were found by Leuckart and 
Lieberkiihn in the gall bladder and the kidneys of toads. Now, the 
assertion, in so far as it concerns Leuckart, is, I suspect, an error. It 
was probably copied from Lutz,* who says: 
The Myxosporidia are, as it is known, entirely parasitic, and in the large major- 
ity of cases live upon fishes. The only one of the authors accessible to me who men- 
tions their occurrence in the Amphibia is Leuckart, who found them frequently in 
thé urinary bladder of frogs, and also mentions the occurrence of a species described 
* by Lieberkiihn in the kidney. 
I have been unable to find any such observation of Leuckart’s, and 
correspondence with both him aud Dr. Lutz failed to elicit a reference 
or a substantiation of the statement; so that “ Leuckart” is here prob- 
ably an error for Lieberkiihn. Furthermore, there is absolutely noth- 
ing to indicate the myxosporidian nature of the forms described by 
1 Bull. U. 8. Fish Com. for 1889, 1x, p. 102. 
?Virchow. Archiv. f. pathol. Anat. u. Physiol., Berlin, cxxm, p. 557; Die Protozoen 
als Krankheitserreger, 1891, 2 ed., p. 134; recently copied by Ohlmacher, Journ. 
Amer. Med. Assoc., 1893, xx, p. 562. 
’Centralbl. f. Bakt. u. Parasitenkde, 1889, v, p. 84. 
