INTORNO AD ALCUNI PROTISTI ENDOPARASSITICr. 203 



" ali atages of the formation of perfect sporangia, from that in 

 which we bave mere irregular aggregations of closely adherent 

 Amoebae . . . to that in which we ha ve perfectly developed spo- 

 rangia, with a distinct investing membrane, and even, in cer- 

 tain cases, an internai meshwork representing what may be re- 

 garded as a rudimentary capillitium . . . After the sporangia 

 have been, as it were, planted out by the aggregation and more 

 or less intimate union of the Amoebae, and the formation of an 

 investing membrane, the process of spore formation normaliy 

 sets in when this is regularly carried out the bodiesof the Amoe- 

 bae become resolved into masses of spherical spores, measuring 

 from 5 to 9 [/. in diameter... As the sporangia mature and dry 

 the spores lose their spherical forni . . . and they become bicon- 

 cave... When a mature sporangium containing such biconcave 

 spores is introduced into a suitable medium, the former very 

 rapidly well out and become spherical, and by their increased 

 bulk exert a constantly increasing tension on the sporangial 

 wall. The capsule ultimately ruptures at one or more points and 

 contracts, forcing the spores out in streams and masses into the 

 fluid . . . The spores give origin to minute Amoebae, but, in cer- 

 tain cases, in place of doing so, they appear to be resolved into 

 flagellate zoospores which swim off actively in the fluid . . . When 

 sporangia are introduced into preparations of freshboiled cow 

 dung they rapidly disappear, and the cultivation within twenty- 

 four hours, in favorable cases, shows an abundant new crop 

 of sporangia. This process may be repeated again and again 

 indefinitely so long as a fresh medium is supplied for each ex- 

 periment; for, as in the case of the naturai development, the 

 soil appears to be exhausted in the process of producing a sin- 

 gle crop. As a rule, in these cultivations we do not find a zoo- 

 sporic stage represented, the spores at once giving origin to 

 amoeboid bodies, which after have increased in size, become as- 

 sociated to form new sporangia . . . The sporangia and spores 

 described above are such as occur by far most regularly and 

 may be regarded as the typical form of reproductive bodies in 



