. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 294 DISCOVERY REPORTS that of the other specimens, this might point to a distinction. For the present, however, this difference seems to be of too httle importance for a specific character, so that I am including the specimens on Thysanoessa in the species Amallocystis fagei. On account of lack of sufficient material for comparison, and owing to deficient knowledge of the structure of the Euphausiacea, no attempt was made to determine the influence of the parasites on the sexual characters of th
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 294 DISCOVERY REPORTS that of the other specimens, this might point to a distinction. For the present, however, this difference seems to be of too httle importance for a specific character, so that I am including the specimens on Thysanoessa in the species Amallocystis fagei. On account of lack of sufficient material for comparison, and owing to deficient knowledge of the structure of the Euphausiacea, no attempt was made to determine the influence of the parasites on the sexual characters of the hosts. It may be observed here that all the parasitized specimens of which 0° QO^ ^^-^^^. Fig. 5. Amallocystis fagei Boschma on Thysanoessa gregaria G. O. Sars from St. 871. Transverse sections of host. Letters as in Fig. i. x 80. sections were made are of the female sex. As already remarked above, the ovary of these infested specimens does not give the impression of being rudimentary or decidedly under-developed. It is quite possible, and it is even to be expected, that in normal specimens of the same size the ovary is much more fully developed. In Einarsson's infested specimens of Thysaiwessa inermis and Th. raschii the ovary appeared to be completely disorganized, and these specimens did not show secondary sexual characters (cf. Einarsson, 1945). The differences in the state of development of the ovary in the specimens from the Antarctic as compared to Einarsson's specimens from the region of Iceland may be due to the fact that in the latter as a rule more than one parasite was found on each infested specimen, whilst in the former the parasite very rarely occurs in more than one specimen on one host. Amallocystis umbellatus Material : St. 81 (32° 45' S, 8° 47' W), 18. iv. 1926, net 450 H, depth of net 650-0 m., i ex. on Hoplophorus novae-zeelandiae De Man (Fig. 11). ^ ^ St. 692 (02" 02' 15" N, 30° 08' W), 9. V. 1931, net TYFB, depth of net 350-0 m.,
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