. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 3o4 DISCOVERY REPORTS antero-laterally with the body just behind the antennules and extends straight forward. The multi- articulate antennal exopod with its long natatory setae is similar in both sexes. It articulates somewhat to the outside of the apex of the shaft, the articulation corresponding exactly in position with the base of the antennal notch of the carapace (Fig. 2). It can be extended through this notch or withdrawn into the carapace and then lies beneath the body of the animal, with
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. 3o4 DISCOVERY REPORTS antero-laterally with the body just behind the antennules and extends straight forward. The multi- articulate antennal exopod with its long natatory setae is similar in both sexes. It articulates somewhat to the outside of the apex of the shaft, the articulation corresponding exactly in position with the base of the antennal notch of the carapace (Fig. 2). It can be extended through this notch or withdrawn into the carapace and then lies beneath the body of the animal, with its natatory setae embraced by the palps of the mouth-parts and the bases of the first trunk-limbs. The broad, flattened basal article of the endopod (Fig. 3) articulates with the shaft on its inner surface near the apex. It bears two short setae which differ in structure in different species. The second article bears two setae of moderate, but unequal length, of which at least the apices are thin- walled. Besides these, in the male there are three very short setae, but not more than one of them is present in the female; in the female of Conchoeia borealis antipoda they are all absent. The end-article bears three 'tube-setae' similar to those of the antennule. In the male there is a clasping organ. Fig. 3. C. borealis antipoda. Right antenna from inside. A, female; B, endopod of male. , clasping organ; en, endopod; ex, exopod; , natatory setae; sh, shaft. (Fig. 3 B, ) which Skogsberg (1920) considered to be a modification of the end-article itself. This is a hook-like structure which differs somewhat in form on the two sides of the animal, and also differs in different species. Normally the longer setae of the ramus extend vertically downwards, just within the anterior gape of the carapace; the ramus can, however, be moved antero-posteriorly. The main adaptation of the antenna is for swimming. The exopod of the appendage can be extended through the antennal notch and
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Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
