34 Distribution of the Smaller Crustacea. [Sess. 



family Lernseidse ; while the other is CJiondracanthus ornatus, 

 and is a member of the family Chondracanthidse. 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 

 Cho7idr acanthus on one side of the head and a ffcemobaphes on 

 the other ; another specimen had a Chondracanthus and a 

 Hcemobaphes 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 

 ffccmobaphes 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 

 Zerncea Iranchialis, 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 Levrwea when 

 young is a free -swimmer, and should therefore be able to 

 attach itself to any fish that happens to come in its way. 



