The myxosporidia of the bEaufort region. 217 



The classification here given is unsatisfactory in several respects. In some cases 

 it groups together in the same family species which are obviously not at all closely related. 

 But the most serious fault is its separation of the Myxosporidia into two divisions based 

 on the number of spores formed by a trophozoite. Nothing can be more certain than 

 that this is a relatively unimportant character. Even within the same species we find 

 considerable variation in this respect. According to Auerbach (1910), Myxidium her- 

 gense is both monosporous and polysporous, and the same is true of a species of Myxidium 

 from the gall bladder of Coitus scorpius, according to Amerinzew (191 1), while Myxidium 

 incurvatum is both monosporous and disporous. Ceratomyxa has always been looked 

 upon as the very type of the disporous group, and yet Ceratomyxa recurvata is both dis- 

 porous and polysporous." On the other hand, Ceratomyxa monospora is both monosporous 

 and disporous. In other genera we find similar examples. Sinuolinea dimorpha occurs 

 in two well-defined forms^one disporous, the other polysporous. Sphcerospora poly- 

 morpha and Chloromyxum granulosum, are also both disporous and polysporous. 



The family Myxidiidae, as defined by Doflein, includes a number of very diverse 

 genera which have few characters in common. Such genera as Sphcerospora and 

 Myxiditim are very unlike and should undoubtedly be assigned to different famiUes. 



On account of the obviously artificial character of Doflein's classification a new 

 arrangement of the genera has been attempted, which, it is believed, much more nearly 

 expresses their natural relationships. It is fully realized that the classification proposed 

 here can be considered only tentative and no doubt will require considerable modifica- 

 tion as knowledge of the group increases. It is, however, hoped that it will serve as a 

 basis for a final classification of the group which will express their real relationships. 



The author fully agrees with Amerinzew (1907) on the importance of other characters 

 in addition to the spores, but with the present limited knowledge of the group any system 

 of classification must of necessity be based, primarily, on the spores. Moreover, it is 

 felt that this must always be the case. The plasmodia show few definite characteristics 

 and oftentimes so closely resemble each other as to render it impossible to distinguish 

 between certain species in the absence of the spores. Furthermore, the trophozoites 

 are often very variable and may have a quite different appearance in different hosts. 



It will be noticed that the proposed division of the Myxosporidia into two suborders, 

 based on the structure of the spore separates the "free" forms from those which develop 

 only in the tissues. Pracdcally all the tissue parasites are characterized by the flat- 

 tening of the spore parallel to the transverse plane, which in these forms always coincides 

 with the sutural plane. As previously pointed out, there is good reason to believe that 

 the tissue parasites are more highly specialized and further removed from the primitive 

 forms than are the "free" species. This division, then, represents something more than 

 a purely arbitrary distinction. 



The only other important change in Doflein's classification is the rearrangement 

 of the genera formerly included in the Myxidiidae. It is believed that the proposed 

 arrangement better indicates the relationships of the different genera, although it is 

 felt that there are several inconsistencies here which can only be cleared up with 

 increased knowledge of the group. 



fl At least two other species of Ceratomyxa were found, which, judging from the number of sporoblast cells in the tropho- 

 zoites, are in all probability polysporous. They are, however, not included in this paper, since only vegetative forms have 

 been available for study. 



