THE APPENDAGES, THEIR INTERRELATION AND FUNCTION 315 



which links the body of the animal with its carapace (Fig. 2, tnx 2 ). In this position the vertical 

 flattened epipod, in the form of a vibratory plate, extends outwards towards the carapace. Plumose 

 setae, arranged in three groups, extend from the margin of this epipod. At the apex of the protopod 

 is the large anteriorly directed endite-like structure, which, as already mentioned, is probably the endo- 

 pod of the appendage. This bears at its apex a group of three pectinate claw-setae, which curve 

 inwards and slightly backwards (Fig. 10). Dorsally and externally to them are three moderately long, 

 anteriorly directed brush-setae. The setae of the endopod may be directed towards the apical claws 

 of the maxillularly palp, but forward movement of the shaft of the maxilla brings them into the region 

 of the distal endites of the maxillule. A degree of ventral extension of the endopod is also possible. 

 Proximal to the endopod, there are on the shaft of the maxilla two groups of setae, borne on slight 

 prominences, which probably represent endites. There are three setae in thedistal group, a long outer 

 brush-seta, a median brush-seta of about half its length and an extremely short inner seta. The more 



02 mm 





Fig. 11. C. borealis antipoda. Right maxilla from inside, en, endopod; ep, epipod; ex, exopod; p, protopod. 



proximal group consists of a brush-seta of about the same length as the longest in the distal group 

 and a much shorter seta. The setae in these two groups are directed towards the distal endites of the 

 maxillule, though their position varies with movement of the shaft and they can be directed more 

 dorsally towards the proximal maxillulary endites. 



The exopod (Figs. 7, 10 and n) is divided into three articles. The first two of these are long, the 

 terminal very short. The articulation of this ramus is slightly to the outside of the distal extremity of 

 the protopod and at rest extends back parallel to the body of the animal. At the apex of the exopod 

 there are two long claw-setae which curve downwards, and a much more slender one. From the lower 

 edge arise a series of setae extending downwards. These setae are in series with a long brush-seta 

 extending downwards from the ventral surface of the endopod. Of them, there are four in a group 

 arising from a prominence at about a third of the length of the proximal article from its base. A further 

 pair arise near its apex. The second article bears a similar single seta about the middle of its length. 

 A second series of setae arise from the median face of the exopod and extend inwards across the 

 mid-line. There are on the first article two of these near to the proximal group of ventral setae and 

 a third near the distal pair. The second article bears a single medially directed seta near its ventrally 

 directed seta. Somewhat dorsally from the outer face arise a third series of setae, which extend back- 

 wards, upwards and slightly outwards. Two of these are near the apex of the proximal article and 

 a third arises at about two-thirds of the length of the second article. 



