THE MYXOSPOraniA, OR PSOROSPEKMS OF FISHES. 2()5 



Myxosporidium. — The largest attaining 75 /< (3V" Liebeikiihn), tlie 

 smallest the size of a blood corpuscle; spherical or ellipsoidul, niore 

 rarely irregular, membraueless, containing irregularly scattered fat-like 

 globules. 



Spore formation. — Many m3^N:osporidia appear destitute of fat gran- 

 ules, but show a large number of structureless gelatinous globules; 

 other myxosporidia show partly the same globules, partly similar ones 

 of the same size containing 4 capsules whose apices are approximated. 

 Many globules show only faint indications of such capsules. Sometimes 

 2 such globules occur inclosed within a common structureless mem- 

 brane. Besides these, developed psorosperms occur, both individually 

 and in heaps, held together by a mucoid substance. 



Spore. — Sharp-contoured, subglobular, mucronate anteriorly; length 

 ad max. J 8 /^<; capsules 4, converging anteriorly. 



Habitat. — Free in urinary bladder of Lota lota L. (ling). Found in 

 about 20 per cent of the fishes examined. 



Bemarlcs. — Lieberkiihn emphasizes the striking resemblance between 

 this species and those described by Ley dig from the gall-bladder of the 

 Plagiostomes {Chloromyxum leydigii and C incisum). He notes, how- 

 ever, that C. mucronatum differs from Leydig's forms in the absence of 

 a membrane around the myxosporidium, and in the absence of the pan- 

 sporoblastic A^esicles (Leydig's Toclitei'hlase). From later researches it 

 is easy to interpret Liel)erkiihn's results in harmony with those of Ley- 

 dig, as the vesicle stage of the pansporoblast is merely a later stage of 

 the gelatinous globules of the above description (see pp. 81, 28G). 



SUBGEN. SPHiEROSPORA Th^lohau, 1892. 

 Etymology not given. 



Bull. Soc. pliiloiiiat. Paris, iv, p. 175; Myxosoma et Mixosoma^ ihid., p. 175; 

 subgen. (including MyxoHoma and Mixosoma) of ChJoromi/xum, Gurley, 

 1893, Bull. U. S. Fisli Com. for 1891, xi, pp. 411-il2, 418-419; Sphwrosjwra 

 et Myxosoma, Braun, 1893, Centralbl. f. Bakt. u. Parasitcukde, xiv, p.739; 

 ib., Braun, Centralbl. f. Bakt. u. Parasiteukde, xv, p. 87. 



Definition. — Bicapsulate Chloromyxa; tyi>e Chloromyxum (S.) elegans. 



Species. — The study which, through the kindness of Dr. Ohlmacher, 

 I was able to make of C. (S.) ohlmacheri enabled me to recognize 2 

 other species in the literature which should be referred to this sub- 

 genus. The first is Balbiani's spore of Accrina cernua, which I have 

 named Myxoholus perlatus. The median anterior and y)osterior mucro- 

 nate projections and the median line shown in Balbiani's figures, can be 

 respectively interpreted only as the ends and the intervening portion 

 of the ridge. In other words, the valve junction plane is vertical. The 

 ai)i)earances are identical with those shown by C. ohlmacheri. The 

 second is Biitschli's spore of the ovary of Lota lota. Though Biitschli's 

 figuies represent it as bicapsulate it should be compared witli C. macro- 

 valiim. 



'Type M;;rnKonuf (hijnrdhiL 



