1'.'16.] NATURAL SCIENCES OF PHILADELPHIA. 



Attention may also be called to the homology of the sarcosporidian 

 muscle stage with the entire schizogonous cycle of the Coccidio- 

 morpha. In the latter, the products of schizogony are set free and 

 are enabled to invade new regions of the host. In the former, a 

 tissue reaction on the part of the host confines them in the region 

 originally invade* 1. 



If the line of reasoning developed above he sound, it seems to 

 follow that the Sarcosporidia are not Xeosporidia, but Telosporidia, 

 and moreover Telosporidia which obviously belongs to the Coccidio- 

 morpha. In the discussion given above, the various characters of 

 the Sarcosporidia and Coccidiomorpha were compared, the result 

 showing both resemblances and differences. But as will be pointed 

 out below, the characters of taxonomic value were those wherein tin 

 two groups were alike, whereas the differences had to do with charac- 

 ters not used in classification. 



Before, however, giving the reasons for regarding the Sarcosporidia 

 to be Telosporidia, it may be advisable to point out the difficulties 

 in the way of regarding them as Neosporidia. This group, which 

 constitutes a subclass of the Sporozoa, is defined by Doflein (1911), 

 p. 701 as composed of Sporozoa which may sporulate during the 

 entire vegetative period. 



Thus, a typical neosporidian will consist of a multinucleate organ- 

 ism, in the cytoplasm of which there will be a number of spores in 

 various stages of evolution. It has apparently always been assumed 

 that something of the sort takes place in the Sarcosporidia; that the 

 cyst originates from a multinucleate element which only secondarily 

 becomes multicellular. As we have seen, however, the cyst is com- 

 posed of separate cells from the very outset. Hence there appears 

 to be no good reason for regarding the Sarcosporidia as Neosporidia. 



We are now in position to suggest, at least tentatively, a new 

 classification for the Sporozoa. This class is divided into two 

 subclasses, the Telosporidia and Neosporidia. In the first, division 

 into multiplicative elements takes place only at the end of the 

 vegetative period. In the second, as we have seen, growth and spore 

 formation take place simultaneously. 



Following Doflein, the Telosporidia may be divided into two 

 orders, as follows : 



1. Coccidiomorpha: 



Vegetative stage continuously intracellular. 



Fertilization anisogamous. 



Sexual generation continuously or transiently intracellular. 



