THE ^EGID^E 347 



Corallana, to which they have been assigned, but infirmi- 

 ties of description have made it impossible for Dr. Hansen 

 to decide these cases. It is only by degrees beginning to 

 be understood that by naming undecipherable species 

 naturalists increase neither the resources of science nor 

 their own reputation. 



Family D. Barybrotidce. 



Barybrotes, Schiodte and Meinert, 1879, is the only 

 genus. The limbs of the pereeon have the seventh joint 

 in the first three pairs forming a strong hook, and all the 

 seven pairs by dilatation of the joints or garniture of setae 

 are auxiliary to swimming. Two species, Indus and agilis, 

 were instituted by the authors of the genus. Hansen finds 

 that these are one and the same, and adopts the name agilis 

 as the most significant, but as Indus has precedence in the 

 original authority, it should be retained. Schiodte and 

 Meinert state that the male has a stiliform appendage on 

 the inner side of the inner branch of the second, third, and 

 fourth pleopods, which would be a truly remarkable 

 feature. But Hansen, who has examined the type-speci- 

 mens, declares that neither here nor in any other Isopod 

 does such an appendage occur on the third and fourth 

 pleopods, it being limited here as elsewhere, to the second. 

 A noticeable feature in the species is that the seventh 

 segment of the pera?on is almost entirely concealed. The 

 animals have only been taken in the open sea. 



Family FJ. 



To discriminate the young of this family from those of 

 the Cymothoidas demands careful scrutiny. It has for this 

 purpose to be noticed that in the ./Egidae the last three 

 pairs of peraeopods have the seventh joint rather shorter 

 than the sixth, and, though a little curved, not forming a 

 hook, whereas in the CyrnothoidaB this seventh joint is not 

 shorter than the sixth and forms a much curved hook. 

 When the animals are adult or half-grown the distinction 

 is easy. In addition to the character already mentioned, 



