Discussion

I have three specimens in all, from two stations, corresponding very well with Behning's figures for this species. Barnard (1930) considers it belongs in Cyllopus and not Vibilia, and in this I certainly agree. However, I disagree with placing it in the synonymy of C. magellanicus, although certainly on the basis of published figures there was good reason for so doing. The species is one of those which have a quite distinctive facies, but in detail are remarkably similar to closely related species in almost all characteristics. The specimens were sorted out as being distinct from C. magellanicus before dissection, but, with the possible exception of the first antennae and certainly the fifth peraeopods, the dissected appendages do not show marked differences from those of C. magellanicus. The differences which Barnard attributed to size are not the differences, in my opinion, between adult and juveniles, but valid differences between adults of species with different size ranges. There is only one detail in which they do not completely agree with Bovallius's and Behning's specimens; that is the greater number of spines on the second gnathopod merus process. (The maxilliped agrees perfectly with Behning's figure.)

Differences between C. magellanicus and C. macropis appear to be: the comparatively stronger shorter peraeopods in C. macropis; the much more rounded (and in my specimens, lighter-coloured) eyes of C. macropis; the comparatively shorter and stronger second antennae and shorter first antennae; the lack of spines on the maxilliped outer plate outer margin; the squarer inner plate of the first maxillae (but this may be an artifact or distortion); the differences in proportion of all gnathopods and peraeopods; differences in proportions of uropods. All of these could possibly fall within the limits of size and sex variation as suggested by Barnard (p. 407) if we were indeed dealing only with the juvenile of C. magellanicus. However, most noticeable of all is the reduction in number of segments in the fifth peraeopod from 5 plus basos in C. magellanicus to 3 plus basos in C. macropis. In all three of my specimens there are only the three plus basos. The proportions are strikingly constant and differ from C. magellanicus, and in each specimen the last segment has a single strong