NEW GENUS OF AMPHIPOD CRUSTACEANS. 
633 
The dark spot which we have pointed out in the oesophagus appears to answer to 
what Claus calls the “ dental plates ” in Plironima ; and the caecal appendage which he 
describes in that animal has, in the present species, assumed so large dimensions as to have 
replaced the stomach, which does not exist morphologically, hut is physiologically 
represented by the caecum. 
Circulation and Respiration. — While the animal was alive I did not succeed in 
seeing the heart. I only saw it when it had been put into weak spirit ; and under the 
same treatment I also saw the nervous system much better than before. The heart is 
an elongated tube extending from the second to the fifth segment (Plate XLIX. 
fig. 3, c). Probably there are three openings in it as in Plironima , one in each segment ; 
but of these nothing could be made out. 
The respiratory organs consist of three pairs of small transparent sac-like gills at the 
bases of the second, third, and fourth pairs of feet (Plate XLIX. fig. 1, hr). They 
are in form and number nearly the same as in Plironima. The water is driven over 
them by the action of the three pairs of abdominal feet. 
Genital Organs. — The single specimen taken is a female. There is a large ovary, 
distinguished by its rose-colour, occupying the middle portion of the first body- 
segment (Plate XLIX. fig. 3, ov). I suspect that it consists of two ovaries lying close 
together, and having two excretory ducts leading to the genital papilla ; but it is impossible 
to ascertain this without mutilating the specimen. The genital papilla is an elevation in 
the centre of the ventral surface of the first thoracic segment between the two limbs, 
which, as I have already mentioned, are destined to bear the eggs at their base, as in the 
females of Nymphon. The colour of the papilla is rose, with scattered scarlet points pro- 
duced by small spines on the surface of the carapace. In the centre of the genital papilla 
there is a large spine (Plate L. fig. 6, d) with a groove leading into a depression (c), 
in which I believe are seated the apertures of the ovarian ducts. This pit is protected 
by two soft appendages (Plate L. fig. 6, Z), answering to the valves which are to be 
found in most female Amphipods, and in which they keep their eggs. In the present 
species, however, they are only rudimentary, and they do not seem' to be used for 
that purpose, as I found the eggs attached to the bases of the first pair of ambulatory 
legs. 
Eggs and Development. — The eggs which I found adhering to the legs had a diameter 
of 07 millim., and were provided with an unsculptured chorion. They contained embryos 
in different stages of development. Unfortunately I discovered this only after the animal 
had been for a night in weak spirit, in which it had been placed for fear it should suffer 
decomposition. 
The main point with regard to its embryology could, however, still be settled — namely, 
that there is no metamorphosis, and that the antennae, the five pairs of thoracic, and the 
abdominal legs are already to be seen in the embryo. Figs. 4 and 5 of Plate L. give 
lateral and dorsal views of an embryo, showing the five ambulatory legs. Embryos in 
the stages which showed the antennae and the abdominal legs were not in a sufficiently 
