240 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



60. Myxobolus spheralis Garley, 1893. 



(Psorosperms of Com/oH»8 /era, Clapar^de, 1874, inLunel's Hist. Nat. d. poissons 



dii biissia du L6inan, pp. 113-14. ) 

 Myxobolus sphernHs, Bull. U. S. Fisli Com. for 1891, xi, p. 415; Myxoholm sphce- 



ralis [error] Braun, 1894, Centralbl. f. Bakt. u. Parasiteukde, xv, p. 87. 



Cyst. — Diameter, 0-25 to 0-33 mm. 



Myxosjioiidiura unknown. 



Spore.-^Very dififerent from tliose contained in the cysts of the 

 muscles of the same fish, untailed, perfectly spherical, 9 /x in diameter, 

 containing a single spherical, very strongly refringent " nucleus " and 

 some small granules. Some cysts contain spores with less refringent 

 nuclei and with very numerous small granules. This difference is per- 

 haps only one of age. 



Habitat. — Cysts imbedded by thousands in the mucosa of the branchiai 

 of Corcgonus fera Jur. Their abundance gives to the branchiae a gray- 

 ish color apparent at the first glance. 



Bemarlis. — Claparede remarks that it might naturally be supposed 

 that a generic bond exists between the small cysts of the branchiae and 

 the large cysts of the muscles, but observation was unable to justify 

 this hypothesis. 



61. Myxobolus sp. incert. PI. 28, fig. 6. 



Psorosperms of Luciopcrca sandra, Miiller, 1841, Miiller's Archiv., pp. 480-6, pi. 

 16, figs. 3a-? ; ih., Miiller, 1843, Raver's Archiv. de Mdd. comp., i, pp. 222-6, 

 pi. 9, fig. Sa-l; ih., Diijardin, 1845, Hist. Nat. d. Helminthes, p. 644; ih., 

 Robin, 1853, Hist. Nat. d. Veg^t. Parasites, p. 295, pi. 15, fig. 5. 



Cysts. — Flat white vesicles or pustules, 1-09 to 248 mm. {h to V") in 

 diameter, usually few and discrete; contents a small quantily of gran- 

 ular matter, mostly, however, consisting of the sjDores. 



Myxosporidium unknown. 



8po)x. — Almost exactly round, untailed or very rarely (once in 200 

 to 300 times) tailed, the tailed forms occurring in the same cyst and 

 resembling especially M. schizurus, from which species, however, they 

 differ in having' the tail no longer or only a little longer than the body; 

 with double-contoured border, thickness equal to one-half the breadth; 

 ridge present; capsules 2, of equal size, converging and appearing as 

 though united by a knot at their anterior extremities (fig. 6a). Among 

 multitudes of typical specimens, Miiller says an occasional one is seen 

 containing 3 bodies, the third being placed behind and between the 

 other two. Spore frequently showing a dark pBuctule just behind the 

 posterior end of each capsule Avhich sometimes simulates an oblique 

 line extending from the border to the capsules; at others, a slight 

 projection of the shell. 



Development: — Traced (naturally enough, but erroneously i) by Miiller, 

 as follows: (1) Spores occur in which the capsules are no longer at the 



'It must be remembered that Miiller was not aware of the existence of the myxo- 

 sporidium. Recently Miugazziui has attemj)ted to revive this view of the office of 

 the capsules (see p. 87). 



