28 PRACTICAL PARASITOLOGrY 



(b) Spharomyxa labrazesi, Lav. et Mesn. 



Myxidium lieberkilkni is not a very good subject for the study 

 of cnidospore formation. Not only is the plasm rich in contents, but, 

 unlike the other Myxosporides, sporulation is simultaneous, thus 

 allowing one developmental stage only to be observed at a time. 

 The parasites found in the gall-bladder are better subjects for this 

 purpose and, of these, Schroeder * considers Splicer omyxa labrazesi, 

 a tenant of the sea-horse, the most favourable. Fresh material is 

 readily obtainable as, up to now, every specimen of Hippocampus 

 brevirostris, Guv., and H. guttulatus, Cuv., examined at Arcachon and 

 Kovigno has been found to contain this parasite. The living organism 

 is of little value for purposes of investigation, however, and fixed 

 and coloured specimens are infinitely to be preferred. 



Sphceromyxa labrazesi is a flat, disclike Protozoon nearly circular 

 in shape. It may attain a diameter of 5 mm., and it never exceeds 

 0'025 to 0'04 mm. in thickness. In colour it is w T hitish, and presents 

 so striking a contrast to the green gall that it may even be seen 

 through the walls of the gall-bladder. Amoeboid movement, especially 

 of the larger individuals, has never been definitely proved. The 

 endoplasm contains a large number of vacuoles. Cover-glass prepara- 

 tions are not very satisfactory. It is better to fix the whole gall- 

 bladder in alcoholic solution of mercuric chloride or Flemming's 

 mixture, cutting sections while the bladder is in the fluid, as this 

 facilitates the penetrative action of the reagent. 



The many nuclei, which are seen surrounded by a small quantity 

 of plasm at the nodes of the alveolar network, are of two distinct 

 types. Either they are large and incompact (female?), or they are 

 small and compact (male ?). In the small masses of plasm which 

 lie between each mesh of the network, there are usually two nuclei, 

 one of each sort. It is evident that this is a case of commencing 

 autogamy, although the two nuclei do not combine until a good 

 deal later ; not until, in fact, each nucleus has divided several times. 2 

 These plasmic masses containing two nuclei are the pansporoblasts 

 of the Myxosporide. In the beginning, owing to the influence of 

 the vacuoles by which they are surrounded, they are amoeboid in 

 appearance, but in a later stage of their development they round off 

 and acquire a firm outline. The two original nuclei continue to 



1 O. Schroder, " Beitrage zur Entwickelungsgeschichte der Myxosporidien," 

 Verhdlg. d. NaturJc.-med. Ver. Heidelberg, N.F., vol. vii, 1907, pp. 455-466 ; Arch. 



f. Protistenkunde, vol. ix, 1907, pp. 359-381. 



2 Compare upon this point, as also upon the analogy between Myxosporides and 

 Amosbae (especially Entamceba coli), M. Hartmann, "Das System der Protozoen," 

 Arch. f. Protistenkunde, vol. x, 1907, p. 143. 



