1 72 REPORT OF THE COMMISSIONER OF FISH AND I'lSHERIES. 



3. Genus et sp. incert. PL 2, fig. 3. 



Parasite of Gadus eaUarias, Miiller &, Retzius, 1842, Ueber parasitisclie Bild- 

 nngen; 1. Ueber eiue eigenthiiniliche Kranklieit der Scliwimmblase beim 

 Dorscb, Gadiis caUarias, Miillev's Arcbiv., pp. 193-8, i^l. 8, fig. 1; ib., Rayer 

 1843, Rayer's Arcbiv. de M6d. comp., i, pp. 284, 287-9, pi. 9, fig. 14; ib., Ley- 

 dig, 1851, Miiller's Arcbiv., p. 22, montion only ; psorosperuis of G. caUarias, 

 Robiu, 1853, Hist. Nat. V^gdt. Parasites, pp. 291, 309, pi. 14, fig. 1; ? psoro- 

 spenn of bladder of codfisb, St. George, 1879, Ucber dieFeinde der Fiscbe, 

 Circ. 3, Deutscb. Fiscb-Verein, p. 178, and Rep. U. S. Fisb Com. for 1878 

 (1880), VI, p. 510; Myxosporidiau? Coccidiau? Biitscbli, 1882, Brouu's Tbier- 

 Reicb, 1, p. 591, footnote; psorosperm of Gadus vierlucciits (error)' Bal- 

 biaui, 1883, .Touro. de Microgr., vii, pp. 145, 280; ib. (error),' Balbiaui, 1884, 

 L(^(^ous sur les Snorozoaires, p. 122; ? psorosperms of cod, v. d. Borue, 

 1886, Handb. d. Fischzncbt u. Fiscberei, p. 211. ^ 



Adult unkuowu. 



Cyst. — Uuknown. Patliologic formation consisting of a whitish-yel- 

 low, pasty mass drawing out into threads of a greasy, dirty character, 

 mostly diffluent (evidently less advanced), with a firmer portion surround- 

 ing the softer, in quantity about 6 fluid ounces, odorless even after several 

 days exposure to the air 5 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 jj, 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 oi^posite 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 a surrounding membrane; some were, however, observed heaped 



'Prof. Balbiani misquotes tbe name of tbebost as "tbe merlucbe, Gadus merluccius." 

 Tbe context (be refers to tbe diseased air bladder) renders it evident tbat tbis is an 

 error for G. caUarias, and not (as migbt be exi^ected) for G. merlangus. luferentially 

 from bis language bo regards tbe form as myxosporidian. Perugia (Boll. Scientif., 

 Pavia, 1890, xii, p. 134) bas followed Balbiani's misquotation. 



2 " Witb tbe cod [Gadus morrliua'] and mackerel [Scomber scombvus'] tbe develop- 

 ment of large psorosperm-luraps witb great emaciation and later ulceration is very 

 well known, and not rarely tbere occurs in fresbwater fisbes, from tbe same cause, a 

 great mortality." 



