THE PARASITE MIXCIIINIA. 455 



Sninmary. 



1. The ifenus Mlnchinia is here shown to helong to the Haplo- 

 sporiflia, instead of to the Ooccidia., among- which it has been 

 placed since it was estabhshed by Labbe in 1896. 



2. Its life-history in Chiton consists of two stages, a trophic 

 and a sporogonic, 



3. Daring the trophic stage a multinncleate individual divides 

 by a process of plasmotomy. 



4. During the sporogonic stage a plasmodium becomes encysted, 

 forms gametes, which fuse in pairs (? autogamy, see page 451) to 

 give zygotes. The zygote breaks up into four sporoblasts, each 

 of which acquires an external membrane drawn out into a tail at 

 each end, and later a thick chitinous coat immediately inside the 

 membranous one. 



5. Crabs, Blennies, and Star-fish eat Chiton, but the spores of 

 Miiichinia pass through unchanged, and are in this way 

 disseminated. 



The Musenms, 

 Oxford. 



P.S. — Since writing the above many Chiton have been kept 

 here in Oxford with free spoi-es of Mincldnia in aerated sea-water. 

 After three or four weeks numerous unopened and unchanged 

 spores, often enclosed in ftecal pellets, were found in the intestine 

 of several of the Chiton. These, which included uninfected and 

 previously infected specimens, were carefully examined and some 

 were cut in serial sections, but in no case did the spores show 

 any sign of opening. All organs of the specimens not previously 

 infected wei^e quite normal. 



This failure of the spores to open when eaten naturally by 

 Chiton, confirms the negative i-esults obtained in the above 

 experiments, and we seem forced to the conclusion that the spores 

 of Minchinia do not open in any part of the digestive tract of 

 Chiton. 



Of course there is the possibility that free spores may be taken 

 in by some miiaute animal in which they germinate before passing 

 back (perhaps by accidental swallowing) into another Chiton. 

 However, no evidence is forthcoming on this point at present, 

 although several Neosporidia have been already described from 

 small marine animals. 



lipjerences. 



1. Alexeieff, A.^ — " Sur le cycle evolutif d'une Haplosporidie 



{Ichthyosporidimn gasterojjhilum)." Arch. Zool. Exper. 

 54 : Notes and Revue, pp. 30-44, May 1914. 



2. Caullery, M., & Mesnil, F.^ — ^" Recherches sur les Haplospor- 



idies." Arch. Zool. Exper. 4*^ ser. iv. pp. 101-181. 1905. 



3. Cepede, C. — " Le cycle evolutif et les affinites systematiques 



de FHaplosporidie des Donax." C.R. Acad. Sc. Paris, 

 vol. 153, p. 507. 1911. 



