THE SPOROZOA 309 



SPOROZOA INCERTAE SEDIS. 



In addition to the five well-characterised orders of Sporozoa de- 

 scribed in the foregoing pages, a certain number of forms have been 

 discovered and described by various naturalists, which cannot be 

 definitely inscribed in any of the above orders. To a large extent 

 the uncertain position of these forms is due to the gaps existing 

 in our knowledge of them. Just as certain genera, ranked in older 

 treatises amongst those of doubtful affinities, have been referred, 

 as the result of more extended studies, to a definite position in the 

 classification of the Sporozoa as, for instance, Karyophagus (p. 208) 

 and Piroplasma (p. 269) so it is probable that a more accurate 

 knowledge of many forms now difficult to classify will bring to 

 light unmistakable relationships between them and better known 

 types. Other forms, again, will perhaps turn out not to be true 

 Sporozoa at all. And finally, when these two classes of organisms 

 have been sifted out, there will perhaps remain a certain number 

 of types which must be ranked as orders truly distinct from any 

 of those described above. Provisionally, three orders may be 

 recognised, besides a certain number of very doubtful types. 



ORDER 6. Haplosporidia, Caullery and Mesnil. 1 



The forms comprised in this order agree in having a very simple 

 developmental cycle, which in its principal features is as follows : The 

 youngest stage of the parasite is a minute rounded corpuscle with a 

 single nucleus. With further growth the number of nuclei increase 

 continually. 2 When full-grown the multinucleate body becomes divided 

 up to form a mulberry-like mass, or " morula," of ovoid or spherical 

 spores, each with a single nucleus, and with no trace of any sort of 

 internal differentiation. From each spore arises one of the corpuscles, 

 which was taken as the starting-point of the life-cycle. The following 

 genera are referred to this order : 



Genus 1. Bertramia, C. and M., 1897, for R capitellae, C. and M., 

 from the body-cavity of Capitella capitata, and for the peculiar parasites 

 occurring in the body-cavities of Rotifers, 3 first described by Bertram 

 [116] in 1892; seen,^ Conn [,130], by Fritsch in 1895, and named 

 by him Glugea asperospora ; named by Zacharks, in 1898, Ascosporidium 



1 The name of this order was written Aplosporidia by Caullery and Mesnil [128, 

 129], but was corrected to Haplosporidia by Liihe [5], since the word is evidently 

 derived from airXovs, simple, and not from dTrXous, unseaworthy. 



a Caullery and Mesnil term the multinucleate trophozoite the plasmodium, but 

 in the typical members of the order it has a definite body -form, and is not in any 

 way amoeboid. 



8 These parasites were seen and studied by the present writer when working in 

 Professor Butschli's laboratory in Heidelberg in 1888. Extraneous circumstances 

 prevented the completion of the studies upon them, and most unfortunately the 

 drawings made of them were lost, but some permanent preparations were kept, from 

 which the figures given above are drawn. 



