268 H. LYNDHURST DUKE. 



transition from cephalont to sporont. Frenzel (14) believed 

 the epiinerite to be absorbed in a manner similar to the 

 assimilation of a tadpole's tail. He found among numerous 

 cephalonts with large epimerites individuals with but a minute 

 projection from the protomerite, and he regarded this as a 

 scene in the gradual absorption of the epimerite. The sudden 

 disappearance he regarded as pathological, and due to 

 changes in the surrounding medium. My own observations 

 point to the same conclusion. The vacuole formation quoted 

 above is plainly due to plasmoptysis, which can be followed 

 under the microscope from its earliest onset to the bursting 

 of the bubble. Further, when the gregarines were examined 

 in a special solution of egg-albumen, NaCl and camphor, as 

 prepared by Professor Biitschli, the vacuole formation was 

 considerably delayed; a fact explicable on the ground that 

 the solution more nearly resembles the natural environment 

 of the gregarine. 



The behaviour of the finger-shaped processes also points to 

 the epimerite being absorbed rather than directly thrown off 

 when the cephalont becomes free. In gregarines which are 

 normally lying free in the gut the processes are never to be 

 seen (figs. 1 and 6). The epimerite is still present, but the 

 processes have been withdrawn during the pi'ocess of separa- 

 tion from the mucous membrane ; just as they are absorbed 

 in Echinomera when the cephalont becomes free in the 

 gut (17). This applies to all the free-lying specimens seen 

 in sections, and to a solitary living form which, together 

 with several cysts and some faeces, was pressed out through 

 the anus during examination of a leech between two slides 



(fig- !)• 



In the living sporont (fig. 1) the extreme anterior end of 



the animal is quite transparent and devoid of granules, a few 



of which, separate from the main endoplasmic mass of the 



epimerite, may be seen showing Brownian movement along 



its anterior border. After some time the whole granular 



body of the gregarine appears to shrink back somewhat into 



the cuticular sheath which envelopes it, and this clear area 



