ON THE CLASSIFICATION OF THE MYXOSPORIDIA. 
4L7 
Myxobolus strongylurus, sp. nov. 
(Psorosperms of Synodontis schal, Miiller, Muller’s Arehiv., 1841, pp. 480-481, t. 16, f. 2.) 
Spore: Body anteriorly blunter than in M. schizurus ; length of body 9 n ; breadth 
5.4 // ; tail single, undivided, very peculiar in being constantly oblique in the longi- 
tudinal plane. 
Habitat: Encysted in skin of head of S. schal from the Nile. 
Myxobolus kolesnikovi, * sp. nov. 
(Psorosperms of Coregonus fera Kolesnikoff, 1886, Veter. Vestnik Kharkoff.,v, pp. 242-248, f. 1-3.) 
Cysts: Numerous (up to 80), spherical or oval, 10 to 30 mm. long by 7 to 20 mm. 
broad. 
Spore : Bound or oval with a sharp anterior end ; tail single or double, thick at 
its origin, attenuating gradually. 
Habitat: Interstitial connective tissue of the thoracic muscles of Coregonus fera 
Jur. 
Kolesnikoff ’s figures show the “double” tail to be merely the separated (lat- 
erally shifted) halves of the really single tail. To this species should probably be 
approximated one of Claparede’s 3 forms, t viz, the tailed form habitant in the muscles 
of C. fera. 
Myxobolus linearis, sp. nov. 
(Psorosperms of Pimelodus sebw and of Platystoma fasciatum Muller, Muller’s Arehiv., 1841, p. 
489, t. 16, f. 10). 
Spore: Body lanceolate-linear; length 3 to 4 times breadth; capsules 2, equal, 
entirely parallel-appressed ; tail single, occasionally double. 
Habitat : Cysts in membrane lining branchial cavity of Bhamdia seb(e Cuv. & V al., 
and in branchial lamellae of Pseudoplatystoma fasciatum L., both from South American 
rivers. 
In cysts at the base of the dorsal fin of Ameiurus melas Baf., from Storm Lake, 
Iowa, a spore occurs which I strongly suspect to be identical with this species, as it 
answers in every respect to the above (rather meager) diagnosis. It is peculiarly 
interesting, as the tail is composed of a dorsal and a ventral half, and is insoluble in 
sulphuric acid (cf. M. macrurus). 
Myxobolus schizurus, sp. nov. 
(Psorosperms of Esox Indus Muller, Muller’s Arehiv., 1841, pp. 477-478, t. 16, f. 1.) 
Cyst: 0.44 to 1.09 mm. in diameter. 
Spore: Body oval, length 12 p; breadth 6 p; thickness one-half the breadth; tail 
stout at origin, 3 to 4 times length of body, very frequently (probably as a rule) more 
or less bifurcate; capsules 2, equal, diverging posteriorly. 
Habitat: In cellular tissue of the eye muscles, in that of the sclerotic, and in that 
between the sclerotic and choroid of Esox Indus in May and June. Miiller failed to find 
it in North American pikes. 
* Dedicated to N. F. Kolesnikoff, who first figured this form. 
tClaparede in Lunel’s Hist. Nat. d. Poissons du bassin du L6man, pp. 113. 
F. C. B. 1891 27 
