313 DISCOVERY REPORTS 



to ensure a strong fixation into the host and to develop into a strongly divided organ for the absorption 



of the food. 



Amallocystis fagei, the species with the comparatively small number of trophomeres, is of a much 

 more simple structure than the other species of the genus. The more or less complicated structure of 

 the latter can be easily explained as modifications of the organization of A. fagei. 



Rhizellobiopsis, the genus established by Hovassse (1926) for the parasite of the Annelid Nephthys 

 ciliata, described by Zachs (1923) as Ellobiopsis (?) eupraxiae, is very similar to Ellobiopsis. The body 

 consists of a rather large trophomere and a number of gonomeres (four in Zachs's figure). The distal 

 gonomere in the figured specimen shows a kind of sporulation reminiscent of that described by Jepps 

 (1937) in E. chattoni. Rhizellobiopsis diflFers from Ellobiopsis by its more or less dichotomously divided 

 root system, but in other respects it has a strong resemblance to the species of Ellobiopsis, especially to 

 E. elongata, in which two gonomeres develop on the top of the gonomere. 



Of the various species described by Coutiere (1911c) in his genus Ellobiocystis, very little is known 

 besides their external shape. It seems to be certain that all these forms are simply attached to the 

 cuticle of their hosts without penetrating into it. They are, therefore, no real parasites, but appear to 

 lead a saprophytic mode of life. 



Parallobiopsis coutieri Collin, which has been the subject of extensive studies by Hovasse (1926), is an 

 organism which differs in many respects from Ellobiopsis and from Amallocystis. This parasite is 

 attached to the cuticle of its host by a well-developed sucker. In the central part of this sucker the 

 cuticle of the host is pierced, and here a protoplasmatic excrescence of the parasite penetrates into the 

 tissues, thereby forming an organ for the absorption of food. The body of the parasite is divided by 

 transverse septa into up to eight or nine divisions, the basal of which is the trophomere. At the top of 

 the latter there are a few flat recently formed young gonomeres. Towards the free extremity the 

 gonomeres gradually become larger, so that the distal gonomere is longer than broad. 



Various opinions have been expressed concerning the place of the Ellobiopsidae in the classification of 

 the Protozoa. Caullery (1910) was inclined to regard his genus Ellobiopsis as a parasitic Peridinean, and 

 with some doubt it is included in this group in Chatton's (1920) monograph of the parasitic Peridinea. 

 After Hovasse (1925 a) had found that the spores of Parallobiopsis are flagellispores, he advocated the 

 view that the Ellobiopsidae form a specialized group of the Flagellata. Afterwards also Steuer classified 

 the Ellobiopsidae among the Flagellata. An entirely different view was expressed by Jepps (1937, 

 p. 642): 'the information at present available seems to me to suggest a fungus relationship rather than 

 any other — although perhaps such speculation is at present unprofitable.' 



In the present paper no results are given of cytological details which might point to the affinities of 

 the Ellobiopsidae with other groups of organisms. The particulars referred to above, however, might 

 indicate that the genera which now are included in the family Ellobiopsidae do not form an altogether 

 homogeneous group. It seems probable that especially Parallobiopsis is very little allied to Ellobiopsis 

 and Amallocystis, and, consequently, when it is a fact that Parallobiopsis belongs to the Flagellata it is 

 not yet certain that Ellobiopsis and Amallocystis too must be regarded as Flagellates. As long as no 

 particulars concerning the sporulation of the last-named genera of more definite value than those at 

 present available become known, no distinct indications in regard to their systematic position can be 

 put forward. 



GEOGRAPHICAL DISTRIBUTION OF THE ELLOBIOPSIDAE 



In its typical form Ellobiopsis chattoni Caullery was once collected at Banyuls-sur-mer in the Mediter- 

 ranean, and on several occasions in the region of the Firth of Clyde. If really all the parasites of this 

 genus consisting of one trophomere with one gonomere which were described or mentioned by various 



