3P)2 SUMMARY OF CURRENT RESEARCHES' RELATING TO 



other freshwater fishes. He gave a detailed account of the minute 

 structure of the animal, and discusses in particular the formation of 

 vacuoles, the mechanism of their emptying, the nucleus, the conjuga- 

 tion, and the division. In the strict sense, perhaps, Ghilodon hexastichus 

 is rather symbiotic than parasitic. It lives on the fishes because it 

 finds appropriate nutriment, probably of a very special sort. In 

 normal conditions it occurs on the fish in small numbers, and may be 

 useful in devouring and destroying the bacteria on the fish. It may 

 be, however, that its prolific multiplication when there is a strong 

 bacterial infection may lead to the more rapid death of the fish by 

 suffocation. 



New Leptomonad in Muscids.* — E. Roubaud describes Leptomonas 

 mesnili sp. n., from the posterior intestine of two species of Lucilia 

 from Brazzaville. It is closely allied to L. mirabilis, and has propa- 

 gative trypanosome forms, furnishing additional evidence that Trypano- 

 soma and Leptomonas cannot be separated. 



Microsporidian parasitic in a Gregarine.f — L. Leger and 0. 

 Duboscq describe Nosema frense/inse sp. n., which lives in the cyto- 

 plasm of a polycysted Gregarine, Frenzelina conformis Dies., a parasite 

 of a crab (Pachygrapsus marmoratus). The microsporidian abounds 

 in the cytoplasm of conjugated and encysted Gregarines, and seems 

 somehow to prevent the formation of gametes. It has an effect like 

 parasitic castration. The parasite sporulates within its host, and the 

 Gregarine cyst becomes a microsporidian cyst. 



Position of SpirochaBta.J — R. Gonder discusses this vexed ques- 

 tion, and comes to the conclusion that the Spirochsets should be 

 regarded as a special order in the group of Flagellata, and, as Hart- 

 mann proposes, in the vicinity of the Trypanosomes. The locomotor 

 apparatus in Trypanosomes— blepharoplast with flagelluni and undu- 

 lating membrane — is not essentially different from the undulating 

 membrane with marginal filament and basal corpuscles in Spirochsets. 

 The nuclear apparatus is, of course, very different. Some notes on 

 Spirochsete pinnae are contributed. 



* C.R. Soc. Biol. Paris, lxiv. (1908) pp. 39-41 (11 figs.). 



f Comptes Rendus, cxlviii. (1909) pp. 733-4. 



J Centralbl. Parasitenk., xlix. (1909) Abtb. i., pp. 190-6 (2 pis.). 



