studies on iriariiu' Oslruco<ls 21!! 



„spriclit fiir eine Tiefseeforni; leider gestatten die Fange keinen sicheren SchluB auf die Tiefe des 

 Vorkommens, da es sich durchweg um Vertikalfange des ofienen Netzes handelt. Am wenigsten 

 tief reicht vou den „V a 1 d i v i a"-Fangen 55 V b (1200 m.), der „A 1 b a t r o s s" erbeutete 

 Vertreter sogar aus nur 100 Faden (185 m.), so daC die Form, wenn sie, wie ich vermute, ein 

 Bewohner groBer Tiefen ist, sicher gelegentlich zu geringeren Tiefen aufsteigt." 



This assumption seems also to apply to G. MiUleri. This species too is probably to be 

 considered as being a form that lives mainly in deep water and that, like many other pelagian 

 forms, undertakes migrations up to lesser depths. 



The specimens of S/S ,,M i c h a e 1 S a r s" and M/S „A r m a u e r H a n s e n'' are 

 stored in B. Z. M., those of the ..Antarctic" (on .slides) in R. M. S. 



Gigantocypris Mulleri n. sp. var. minor n. var. 



In one of the samples of plankton from S/S „M i c h a e I S a r s" were found 

 two sexually mature females of this genus, which, although they bore a rather great resemblance 

 to the species described above, differed from it so essentially in so many respects that it seemed 

 to me best, as a preliminary, to distinguish them as a special foim. This form has been arranged 

 as a variety under the above-mentioned species and has not been set up as a new species 

 especially for two reasons, partly because the preceding species appeared to be not inconsiderablv 

 variable and partly because one of the two specimens in question resembled this species consid- 

 erably more than the other in several respects. It is not impossible that we are dealing with 

 specimens of the above-mentioned species whose development has been checked by unfavourable 

 conditions. The answer to this question can only, however, be obtained after renewed investi- 

 gations, carried out with more abundant material. 



To enable the reader to decide how far the two specimens resembled or were different 

 from the type species it seemed most convenient in the description to call one specimen (the 

 most divergent) the a-specimen and the other the b-specimen. 



Description : — Female: — 



Shell: — Length: Specimen a attained a length of 9 mm., specimen b 10 mm. Tlie 

 shape was about the same as that of the type species, but somewhat less globular, however: 

 proportion of length : height : width about 10 : 8 : 7. thus somewhat lower than the type 

 species. The medial bristles were considerably fewer than in the type species, but varied verv 

 much in number; on the rostrum of specimen a about 45 bristles were found (cf. fig. XXX, on 

 which all the bristles are drawn), on the rostrum of specimen b about 60; on the list behimi 

 the incisur about 40 — 60 bristles were found on the former specimen, about 40 — 50 on the latter. 

 Otherwise there was agreement with the type species. 



First antenna: — The proportion between the joints is about the same as in the 

 type species; the second joint is, however, somewluit longer comparatively; the third joint, 

 on the other hand, is somewhat shorter comparatively. The anterior bristle of the third joint 

 is fixed at about the middle of the joint (in specimen a) or just proximally of this. All the 



