206 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 

 Earn. MYXOBOLlDzE Ginley, 1893. 



(Mijx.osporidiecc'^ Perugia, 1891, Boll. Scientif., Pavia, xiii, p. 28; Myxobo- 

 Ices Thelohan, 1892, Bull. Soc. plillomat. Paris, iv, pp. 173, 176.) 



MyxohoUdw, Bull. U. S. Fibli Com. for 1891, xi, p. 413; Myobolea [Thel.] 

 Braun, 189.3, Centralbl. f. Bakt. u. Parasitcukde, xiv, p. 739; ib., Braun, 

 1894, Ceutralbl. f. Bakt. u. Parasitenkde, xv, p. 86. 



Definiiion. — Phcenocystcs, wliose spores are destitute of autero-pos- 

 terior, but possess bilateral, symmetry;^ capsules 2, in 1 group at the 

 auterior eud; a bivalve sliell, tlie plaue of junctiou of whose valves is 

 parallel to the longitudiual plane; an iodiuophile vacuole; type (and 

 only) genus Myxoholus. 



IV. MYXOBOLUS Biitschli, 1882. 

 Etymology not giveu. 



Bronu's Thier-Eeicli, i, pi. 38, figs. 6-10, and of subsequent authors; ^'^-jLauk- 

 ester, 1885, Encycl. Britan., 9 ed., xix, p. 855; ih., Tbdlolian, 1890, Auual. 

 de MicrogT., ii, p. 213; Myxosporidium^ Perugia, 1891, Boll. Scieutif., Pavia, 

 XIII, p. 23; ih., Weltner, 1892, Sitzgsber. Gesellsch. Naturf. Freunde 

 Berlin, p. 34; Myxosportdium, ihid., p. 35; Myxoholus et Henneguya^ Thelo- 

 han, 1892, Bull. Soc. philomat. Paris, iv, pp.176, 177; Myxoholus, FevTier, 

 1893, Trait6 de Zool., p. 460; ih., Gurley, 1893, Bull. U. S. Fish Com. for 

 1891, XI, pp. 411-13; i&., Braun, 1894, Centralbl. f. Bakt. u. Parasitenkde, 

 XV, p. 86. 

 Befinition. — Characters, those of the family. 



Hennegiiyais separated from Myxoholus hy only 2 characters, viz, (1st) 

 capsules constantly 2, and (2d) the presence of a tail. Inasmuch, how- 

 ever, as all the numerous typical Myxoholus species have 2 capsules, and 

 only 2 species are known to deviate in this resj)ect in the direction of 

 capsule-reduction, the typical number of capsules in Myxoholus is 2; so 

 that the 2 differential characters in reality reduce to the siugle oue of 

 the presence of a tail. Tliis in itself is not sufficient to warrant a 

 generic separation, especially in view of the entire accord between the 

 tailed and uutailed forms in regard to symmetry, similar position of the 

 valves, exactly similar vacuole, nuclei, etc. Besides, it may be noted 

 that it has been several times asserted that tailed and uutailed forms 

 occur in the same cyst. Thus Miiller,^ Lieberkiihn,'^ and Biitschli'' 



^ Myxosporidiiim Perugia (synonym for Myxoholus Biitschli?) proposed as type 

 of Fam. Myxospovidiece Perugia, by the author in Bull. U. S. Fish Com. for 18!)1, 

 XI, p. 413. 



^Except species which have stilfcred reduction of characters {Myxoholus unicapsu- 

 latus, M. inrlformis, M. ineqiialis). Perhaps M. strongylurus should be added. 



^ Myxosporidium merlucii proposed by the author (Bull. U. S. Fish Com. for 1891 

 (1893), XI, p. 413) as the type species. The name Myxospovidium, having been pro- 

 posed as a new name for a genus formed by the fusion of several good genera each 

 of which already possessed a name in good standing, must be suppressed. 



^ Henneguya psorospermiea proposed as the generic typo by the author (Bull. U. 

 S. Fish Com. for 1891 (1893), xi, p. 413). 



5 See Myxoholus sp. 61, p. 240. 



^iMiiller's Archiv., 1854, p. 6; M<5m. Cour. ct ]SIom. Sav. fitrang. Acad. Roy. Belg., 

 1855, XXVI, p. 37. 



'Bronn's Thier-Reich, 1882, 1, p. 597. This is probably only an opinion as to the 

 consensus, and not an independent one. 



