172 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
3. Genus et sp.incert. Pl. 2, fig. 3. 
Parasite of Gadus callarias, Miiller & Retzius, 1842, Ueber parasitische Bild- 
ungen; 1. Ueber eine eigenthiimliche Rranthert der Schwimmblase beim 
Biondahe Gadus callarias, Miiller’s Archiv. , pp. 193-8, pl. 8, fig. 1; id. , Rayer, 
1843, Rayer’s Archiv. de Méd. comp., I, pp. 284, 287-9, pl. 9, fig. 14; ib. , Ley- 
dig, 1851, Miiller’s Archiv., p. 22, mention only; psorosperms of G. callarias, 
Robin, 1853, Hist. Nat. Végét. Panes, pp. 291, 309, pl. 14, fig. 1; ? psoro- 
sperm of bladder of codfish, St. George, 1879, Ueber die Feinde der Fische, 
Cire. 3, Deutsch. Fisch-Verein, p. 178, and Rep. U. 8S. Fish®om. for 1878 
(1880), v1, p. 510; Myxosporidian? Coccidian? Biitschli, 1882, Bronn’s Thier- 
Reich, 1, p. 591, footnote; psorosperm of Gadus merluccius (error)! Bal- 
biani, 1883, Journ. de Microgr., vu, pp. 145, 280; ib. (error),' Balbiani, 1884, 
Lé¢cons sur les Sporozoaires, p. 122; ? psorosperms of cod, v. d. Borne, 
1886, Handb. d. Fischzucht u. Fischerei, p. 211.2 
Adult unknown. 
Cyst.— Unknown. Pathologic formation consisting of a whitish-yel- 
low, pasty mass drawing out into threads of a greasy, dirty character, 
mostly diffluent (evidently less advanced), witha firmer portion surround- 
ing the softer, in quantity about 6 fluid ounces, odorless even after several 
days exposure to the air; microscopic examination showing it to consist 
of the below-described corpuscles with a small amount of granular 
matter, the whole imbedded in and held together by a mucoid sub- 
stance. 
Spore.—Best described by comparison to a ribless ventricose Navi- 
cula or to Agardh’s Frustula caffeaformis, elliptic, length pretty uni- 
formly 14 to 17 yw, consisting of two valves, the substance of which is 
Shown by complete decomposition upon ignition to be nonsiliceous; 
their carbon incinerates with difficulty; each valve of an elliptic outline 
with a convex outer and a concave inner surface, usually in contact 
with its fellow of the opposite side by the inwardly convex middle 
portion of its border, the borders of the valves diverging towards their 
ends; sometimes obliquely set so as to be in contact by one end only, 
sometimes in contact for their whole length, thus forming a lenticular 
corpuscle, along the median line of which the junction can be plainly 
traced; middle of valves cemented together by a mass occupying part 
of the body cavity; mass showing more or less plainly a number of 
large and small granules, and apparently destitute of a surrounding 
membrane. 
Development.—By far the largest number of the corpuscles are desti- 
tute of asurrounding membrane; some were, however, observed heaped 
1 Prof. Balbianimisquotes the name of the host as ‘‘ the merluche, Gadus merluccius.” 
The context (he refers to the diseased air bladder) renders it evident that this is an 
error for G. callarias, and not (as might be expected) for G. merlangus. Inferentially 
from his language he regards the form as myxosporidian. Perugia (Boll. Scientif., 
Pavia, 1890, x11, p. 134) has followed Balbiani’s misquotation. 
2“ With the cod [Gadus morrhua] and mackerel [Scomber scombrus] the develop- 
ment of large psorosperm-lumps with great emaciation and later ulceration is very 
well known, and not rarely there occurs in freshwater fishes, from the same cause, a 
great mortality.” 
