12 Distribution of the Smaller Crustacea. [Sess. 
family Lerneide ; while the other is Chondracanthus ornatus, 
and is a member of the family Chondracanthide. Usually 
only one specimen belonging to one or other of the two species 
is found on the one fish, but sometimes two, and even three, 
specimens are obtained on the same fish, and in that case they 
may both belong to the same species, or both species may be 
represented. For example, one of the fishes examined had a 
Chondracanthus on one side of the head and a Hemobaphes on 
the other; another specimen had a Chondracanthus and a 
Hemobaphes on the same side; while a third had two Chon- 
dracanthi, both being on the same side. A sample of fifty- 
five fishes yielded twenty-three parasites, and comprised fifteen 
Hoemobaphes and eight Chondracanthi. Both species were un- 
described. Though the parasites are moderately large, it is 
difficult to make out, without dissection, whether they are 
present or not; and probably it is on account of this, and 
because the spotted dragonet is a fish that is not very common, 
that these parasites were not sooner observed. 
The fish parasites referred to in the preceding notes differ 
greatly in their sexual forms, for while the females are com- 
paratively large the males are usually very small, and, more- 
over, the females in their adult stage are fixed to their host 
for life, though the males are to some extent free, and may 
therefore be found adhering to different parts of the body 
or appendages of the female. Notwithstanding this difference 
in the adult stage of the female and male, the female in its — 
earliest stage is also usually a free-living organism. During 
this early stage in the life of these parasites, the difference 
between the species, or at least between some of them, is 
scarcely, if at all, recognisable; and because of this close 
identity it has been suggested that the changes observed in 
their adult forms, and which have led to their separation 
into distinct species and genera, are simply the result of the 
difference in their host, or the particular part of the host to 
which they have fixed themselves. Take, for example, the 
Lernea branchialis, so frequently found on the gills of whiting, 
cod, and other Gadoids, and which has. the appearance of 
a red worm twisted round upon itself. The Zernwa when 
young is a free-swimmer, and should therefore be able to 
attach itself to any fish that happens to come in its way, 
