766 SUMMAKY OF CUBRENT RESEARCHES RELATING TO 



the oscillating fringe described by Stein is probably caused by two 

 flagella. 



DimorpJius muris n. sp. is described more fully. 



Of parasitic ciliate Infusoria were observed Trichodina tntonis 

 n. sp., from the intestines of Triton (probably identical with the 

 Trichodina known to inhabit the bladder of the Tritons), Balautidium 

 coli Stein (in the pig), Plagiotoma cordiformis and lumhrici, Opalina 

 ranarum, dimidiata, and trigona. 



Psorosperms of Fishes.* — Professor 0. Biitschli here deals with 

 the Myxosporidia, or fish-psorosperms, which are so widely dis- 

 tributed as parasites in fishes. They appear, at any rate in the 

 case of Cyprinoids, to especially affect the gills, where they have 

 the appearance of small white pustules ; they undergo their develop- 

 ment in the layer of connective tissue which separates the two 

 ej)idermal layers of the gill-lamella, and they come therefore into very 

 close contact with a rich supply of capillary vessels. The myxospori- 

 dium, when closely examined, is found to be a more or less consider- 

 able mass of protoplasm, which always contains a large number of 

 spores at various stages in development. There is no difference 

 between an ecto- and an endoplasm. The author was able to satisfy 

 himself as to the existence of a distinct investment, which did not, 

 however, belong to the category of ordinary envelopes, but was of a 

 plasmatic nature, for it was clear, and finely granular, and had a 

 number of small nuclei imbedded in it. 



Contrary to the opinions of some investigators, Dr. Biitschli states 

 that the protoplasm is thickly interspersed with a very large number 

 of small, though distinct, nuclei. 



The covering or shell of the spores has a remarkable resistance to 

 reagents ; it contains a cloudy protoplasmic substance in its posterior 

 portion, while the anterior is largely occupied by the so-called polar 

 corpuscles. These last are capsules with a pretty thick wall, 

 within which there is rolled up a long pale filament, so that the whole 

 structure has a very striking resemblance to an urticating capsule. 



After discussing the way in which this is ejected, the author 

 directs attention to the striking fact that there is certainly a nucleus 

 in the plasmatic contents of the spores. With regard to the general 

 characters of the spore-formation, it is to be noted that their develop- 

 ment is not confined to any special adult stage of the myxosporidium , 

 but that they are to be found at all ages, and in the most different 

 forms. The ripe spores have an elongated-spindle shape, the envelope 

 is distinct and pretty thick, and often striated . 



Biitschli's 'Protozoa.' — In the 8th and 9th parts of this work 

 Professor 0. Biitschli deals with the geographical distribution of 

 the Ehizopoda, and with their palaeontological history (the account 

 of which is communicated by C. Schwager). He then passes to the 

 Heliozoa, and quotes the titles of fifty-one papers on this small 

 group ; the forms which compose it are divided into the several 

 subdivisions of Aphrothoraca, Chlamydophora, Chalathoraca, and 



* Zeitschr. f. wiss. Zool., xxxv. (1881) pp. 629-51 (1 pi.). 



