ELLOBIOPSIDAE 309 



(6) Amallocystis capillosus Fage, type specimens 



Host and manner of attachment : Pasiphaea tarda Kroyer, base of rostrum. 



Number and arrangement of trophomeres : About fifty, in two bundles, at each side of the rostrum 

 of the host one. 



Shape of trophomeres and gonomeres : Trophomeres with long slender stalks, cylindrical or basal 

 part conical, length i-i -3 mm., diameter 0-25 mm. (Fage, 1938, text, 0-025 mm. ; ibid., fig. 2, 0-25 mm.). 

 Gonomeres cylindrical. 



Number of gonomeres on each trophomere : Not more than one. 



Dimensions of gonomeres: Transverse diameter 0-25 mm. Length twice the breadth or more. 



Organ of fixation : A hyaline plate with rough surface, in transverse position under the rostrum, 

 extending at each side into an excrescence penetrating through the cuticle of the host. 



(7) Amallocystis capillosus Fage, specimens from the Discovery collections 

 Host and manner of attachment : Pasiphaea acutifrons Bate, base of rostrum. 



Number and arrangement of trophomeres: About fifty to seventy (originally probably more), 

 arranged in two tufts each to one side of the rostrum. 



Shape of trophomeres and gonomeres : Trophomeres more or less cylindrical with a proximal part 

 tapering into the long slender stalk; gonomeres elongately oval. Trophomeres about twice as long as 

 gonomeres. 



Number of gonomeres on each trophomere: Not more than one. 



Dimensions of gonomeres: Length about o-6 mm., transverse diameter from 0-15 to 0-25 mm. 



Organ of fixation : Irregularly globular, in its upper part with excrescences penetrating through the 

 cuticle of the host, in its lower part possessing a sieve plate forming the connexion of the organ of 

 fixation with the proximal part of the root system. 



(8) Amallocystis sp., Einarsson {Amallocystis fagei Boschma) 



Hosts and manner of attachment: Thysanoessa inermis (Kroyer) and Th. rascliii (M. Sars), dorsal 

 surface of the carapace in the region of the genital gland or (exceptionally) in the region of the stomach. 

 As a rule more than one parasite on each host. 



Number and arrangement of trophomeres: Numerous trophomeres (about thirty ?) spreading from 

 the external part of the organ of fixation. 



Shape of trophomeres and gonomeres : Trophomeres conical to cylindrical, gonomeres globular to 



oval. 



Number of gonomeres on each trophomere : Up to nine (from one to ten constrictions in the sausage- 

 like elongations, Einarsson, loc. cit.). 



Dimensions of gonomeres : Transverse diameter approximately 100/^ (measured in fig. 83 of Einarsson, 



loc. cit.). 



Organ of fixation : Consisting of an internal irregularly oval part and an external part divided into 

 the basal extremities of the trophomeres, the two parts connected by a rather narrow neck. 



(9) Amallocystis fagei Boschma, specimens from the Discovery collections 



Hosts and manner of attachment: Eiiphaiisia vallentitii Stebbing, E.frigida H. J. Hansen, E. recurva 

 H. J. Hansen, E. lucens H. J. Hansen, E. hemigibba H. J. Hansen, Thysanoessa gregaria G. O. Sars. 

 Dorsal surface of carapace in the region of the genital gland. 



Number and arrangement of trophomeres : Parasites of Euphausia vallentini and E. frigida, thirty to 

 fifty; parasites of E. recurva, E. lucens, E. hemigibba and Thysanoessa gregaria, ten to fifteen. In a single 

 tuft spreading from the external part of the organ of fiixation. 



