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ON COPEPODS LIVING IN THE NOSTRILS OF FISHES — 155 
species belonging to the Ergasilidz noticed in this paper is 
twenty-two, and thirteen of them belong to the genus 
Bomolochus. On referring to the habitats of the various 
species, not only of Bomolochus but also of those belonging 
to the other two genera, we find that in no case are any of 
them described as occurring in fishes’ nostrils. This is the 
more remarkable from the fact that Lomolochus does not 
seem to be at all rare, especially in the nostrils of the Cod. 
Moreover, the Copepods are not limited in their distribution 
to the Cod-fishes of the north-east of Scotland, for my son 
informs me that quite recently he has found them in the 
nostrils of Cod caught in the Irish Sea. Asa matter of fact, 
they are found in the nostrils of most of the Cod-fishes I 
examine ; frequently several, and occasionally a considerable 
number of, specimens are found in the nostrils of a single 
fish. In the nostrils of a moderately large Cod from the 
Moray Firth I found as many as twenty-nine specimens of 
Bomolochus. They included males, females (carrying ovisacs), 
and young. In the nostrils of another Cod caught in the 
salmon-nets in the Bay of Nigg, near Aberdeen, twenty-four 
specimens were obtained ; several of these, when removed 
from the mucus with which they were surrounded and put 
into clean water, were very lively and very pretty. In 
seeking for them, the method I adopt is very simple. With 
the edge of my knife I press gently but steadily on the skin 
behind the nostrils till the mucus is forced out of the 
openings, when the Copeods, if they be present, usually appear 
as whitish specks amongst the mucus; but as some may be 
more transparent than others, it is better to transfer the 
mucus into some water in a shallow glass vessel placed on 
a sheet of black paper, or other dark-coloured substance. 
The mucus can then be spread out with a camel’s-hair pencil, 
when the Copepods will come clearly into view, and especially 
if the eyes be assisted with a hand-lens. 
The fact that the same species of Lomolochus should be 
found in the nostrils of such distinctly different fishes as the 
ee the Cod, and the Plaice, is of interest as showing 
a greater adaptability than would seem to be the case with 
some other of our parasitic Copepods affecting fishes. 
