A NATURAL PUZZLE ype 
waters, the Cheraphilus echinulentus of Michael Sars, 
aud Cheraphilus neglectus, G. O. Sars. The last-named 
author, however, has quite recently been able to make 
a very unexpected contribution to the settlement of the 
question, for, in examining the development of different 
members of the family, he has found that the various 
genera and species are often more strongly distinguished 
in the larval forms than in the adults, so that the 
hesitation felt about separating, for example, the species 
Crangon vulgaris and Crangon Allmanni, or the genera 
Cheraphilus and Pontophilus, can no longer reasonably be 
persisted in. Cheraphilus, it may be mentioned, agrees 
with Crangon in having five pairs of branchiz attached 
respectively to the five pairs of trunk-legs, but Pontophilus, 
while agreeing with Cheraphilus in the shortness of the 
second legs, differs both from it and Crungon in having six 
pairs of well-developed branchie, besides a rudimentary 
pair on the second maxillipeds. Since the species Lgeon 
fasciatus, Risso, has been provided by nature with a re- 
markable brown band across the fourth segment of the 
pleon and similar colouring on the tail-fan, as if to sepa- 
rate it unmistakably from ail other species, and to enable 
the collector to identify it without further trouble, it may 
be well to notice that Cheraphilus neglectus also has a deep 
brown band across the fourth segment of the pleon and a 
narrower one across the tail-fan, so that after all the col- 
lector has need to be cautious. 
The arctic Sabinea septemcarinata (Sabine) agrees with 
Pontophilus in the branchial formula. In describing it in 
1821 Sabine calls attention to the fact that the second legs 
are ‘unarmed,’ that is, simple or not chelate, and, while 
recognising that this is an ‘essential point’ of distinction 
from the known species of Crangon and Pontophilus, he 
enters one of the common but always useless protests 
against the multiplication of genera. If he spoke thus in 
1821, what would he have thought in 1891? Kroyer, 
who redescribed the species in 1842, after stating that it 
is very abundant at Spitzbergen, adds that he had found 
the stomach of the seal Phoca burbata quite filled with it. 
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