214 Proceedings of the Royal Physical Society. 
There is no doubt, however, that the present form is as distinct from Chloro- 
myxum as Henneguya is from Myxobolus, and I therefore propose to give it the 
name of Agarella 1 gracilis gen. et sp. nov., and the family Chloromyxide will 
contain at present two genera, Chloromyxum and Agarella. Doflein [5] long 
ago suggested that “eine Parallelreihe mit je vier Polkapseln zu jenen 
Formen mit je zwei Polkapseln existiert,” although “alle Typen sind zwar 
noch nicht gefunden worden,” and in this sense Henneguya and Agarella are 
parallel forms, the former with two, and the latter with four, polar capsules. 
Most of the Chloromyxide, including Thélohan’s C. cawdatum mentioned 
above, are parasites of the gall bladder either of fishes or of reptiles. In view 
of the peculiarly primitive characters of the Dipnoi, it is interesting to note 
that the only two species of Chloromyxide described from tissues, with the 
exception of a problematical form described by Tyzzer as forming cysts in the 
muscles of fish, are Chloromyxum proteus Joseph from the kidney tubules of 
the Amphibian Proteus anguineus from Carniola and Agarella gracilis mihi, 
from the testis-follicles of the Dipnoan Lepidosiren paradoxa from S. America. 
Far too little is known, however, of the distribution and occurrence of the 
Chloromyxide to permit us to draw any conclusions from this fact. 
The mature spores are seen in the cyst in Fig. 1, but in every section of an 
infected testis they are quite numerous also in the pigment (?) cells which 
occur in the capsule of the testis. These pigment-cells may be found, though 
rarely, in the testis-follicles, as was pointed out to me first by Dr Agar, and 
they apparently collect the adult spores, presumably after rupture of the cyst 
wall. Certainly the spores contained within such pigment-cells show signs 
of nuclear degeneration, and perhaps one of the functions of these pigment- 
cells may be that of collecting foreign and waste bodies from the testis- 
follicles; but they are never found in blood capillaries, and are peculiar 
apparently to the testis tissue. 
It is, however, by the study of smear preparations that the development 
of the sporoblast is best followed, as Thélohan [13] long ago pointed out, 
owing to the fact that the cyst or plasmodium is burst by the operation of 
smearing-and the individual pansporoblasts are thus isolated. The following 
account of the spore development is based, therefore, on smear preparations 
only. 
Auerbach [2 and 3], in his papers on Myxosporidia of Norwegian fish, has 
given the best and most connected account of the spore development in this 
group, and, according to him, the first stage is the formation of macro- and 
micro- gametes from macro- and micro- gametocytes. The next step is “je ein 
Macro- und Micro- gameten copulieren,” and in the cases where a synkaryon 
1 After Dr Agar who collected the material on which the description is based, 
