NOTES AND MEMORANDA. 
485 
were found. Cyanea I have never seen in this estuary 
except at high tide. I may mention that the scyphostoma 
and strobila of Aurelia is found with the above-mentioned 
Hydroids attached to the piles of W. Boston Bridge ; but 
the scyphostoma of Cyanea I have never foiind.’^ — E. Bay 
Lank ESTER. 
On the Respiration of the Crustacea. — In the note pub- 
lished in the April number of this Journal, a prediction was 
hazarded that the Zoea larva of the higher Crustacea would 
on examination prove to breathe in the same way as the 
Copepoda. Zoeas of Cancer, and probably of some species 
of Prawn, received from Mr. T. Bolton, have confirmed this 
amply. The respiratory diastole and systole of the rectum 
with rhythmical openings of the anus are thoroughly well 
marked. It may here be noted that in carmine stainings of 
the entire Copepoda the stain does not diffuse through the 
integument, but up through the rectum in the first instance. 
The power of dialysis through the chitinised integument is 
slight if at all existent. Now that another place is found 
for the respiratory function, it may be denied to the 
expanded pleura of the carapace. 
This constancy of function in the anus is remarkable, and 
indicates that the gills which characterise so many of the 
higher Crustacea are secondary formations, long posterior to 
the differentiation of the class. What, then, is their origin ? 
Probably they are in all cases modifications of those pro- 
cesses of the appendages which primitively bring about 
nutritive currents. In Daphnia we have the stage where 
these processes are the exclusive food bringers, while they 
share respiratory functions with the rhythmically contrac- 
tile rectum. And as a parallel to the direction of the bran- 
chial current from behind forwards in the Crustacea, we 
may cite the Lameilibranchs, where the gills, probably in 
origin also parts of the locomotive apparatus (according* 
to Lankester’s view) play an equal part in nutrition and 
haematosis. To explain body gills we have to invoke either 
the principle of the similar modification of neighbouring 
parts, or else that of displacement upwards from the appen- 
dages. As far as I know, for there are none of the memoirs 
on this subject within reach, the development of the body- 
gills of the crayfish, which might give a clue, has not been 
worked out. — Marcus Hartog. 
