472 PROFESSOR CHARLES CHILTON ON THE 
WALKER’S figure is taken from a male specimen, and shows the long second antennz 
found in that sex; these are longer than in the males of Orchomenopsis chilensis 
(Heller) and some other allied species. The occurrence of some specimens with long 
lower antennze was pointed out by PFEFFER in his original description. 
Whether it was necessary to establish the new genus Waldeckia for this species 
appears to me to be doubtful, but as that has been done I am referring the species to it. 
As mentioned above, Steppine in his Tierreich Amphipoda placed the species under 
Orchomenopsis, and the affinities of the species seem to me to be distinctly with species 
of that genus such as O. chalensis (Heller) and O. nodimanus Walker. It is true that 
CHEVREUX has described the propod of the first gnathopod of W. obesa as being simple 
and not subchelate ; but in my specimens, although the propod narrows very considerably 
distally, there is a distinct though short palm, and this is shown also in the figures given 
by Prerrer and Watker. Moreover, there are considerable differences in the breadth of 
the propod in other species of Orchomenopsis, as will be seen from my discussion of 
O. chilensis (Heller) ; and in the South African specimens which I refer to that species 
the propod narrows distally in the same way, though not to the same extent, as in 
W. zschaui. 
The other important point in which Waldeckia differs from Orchomenopsis, as first 
pointed out by CHEvREUX, is in the possession of finger-like accessory branchie. 
CHEVREUX describes one of these as being present on all the legs, and two on the fourth. 
In the specimens I examined | found them on the fourth, fifth, and sixth legs only, and 
only one on the fourth. They appear to arise either from or near the base of the branchia. 
They are long and finger-like in shape, but seem to differ in internal structure from the 
branchia, being filled with granules or globules of some kind, and whether they are really 
branchial in function is perhaps doubtful. This, however, is neither the time nor the 
place for a discussion of their physiological importance; the question that concerns us 
now is their presence or absence, and their value when present as a generic character. 
Secondary or accessory branchiz have been described in several genera of the 
Amphipoda belonging to quite different families, and it seems probable that they may 
be independently developed in cases where there is special need for them, and that their 
presence is not of great taxonomic importance. Tor example, they occur in some species 
of Hyalella and not in others, and the species in which they occur are nevertheless 
retained under the genus Hyalella. It was not till after I had written down the 
general considerations given above that I had an opportunity of specially looking for 
accessory branchiee in other allied species ; but afterwards, on examining large specimens 
of Orchomenopsis chilensis Heller (=O. rossw Walker), from Station 411, whence 
the Waldeckia zschawz had been obtained, I found them in that species also, though 
they appear to be present only on the fifth and sixth legs. Unfortunately, my atten- 
tion was not specially directed to this question till it was too late to make an examina- 
tion of other specimens, but the facts detailed above show, I think, that Waldeckia is 
nearer to Orchomenopsis than might appear at first sight. 
—, —ae 
