THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[SEVENTH SERIES.] 



No. 8. AUGUST 1898. 



XIII. — Further new Parasitic Gopepods found on Fish in the 

 Indo-tropical Region. By P. W. Bassett-Smith, Staff- 

 Surgeon R.N., F.Z.S., F.R.M.S. 



[Plates III. -VI.] 



During the past year, owing to H.M.S. ' Cossack' having 

 visited a variety of harbours in the Indo-tropical region, the 

 opportunity has been given me of adding considerably to what 

 I had already seen at Bombay of these curious little parasites; 

 continued research has shown very clearly that they are 

 abundantly represented. In most cases, when inspectino- 

 any number of well-grown fish (for it is certainly more 

 common to find the mature fish infested with one or more 

 parasites than the younger ones), careful examination would 

 bring to light some actively moving Caligus in the gill-cavity 

 or perhaps a more bizarre and anomalous form, attached to 

 the lips, body, or elsewhere. One point has been very 

 strongly impressed on my mind, namely the constancy with 

 which most of them are found on any particular kind of fish ; 

 and one can predict with almost certainty the form that will 

 be found, though at the same time it appears that one species 

 may at times be taken on two or more distinct " hosts." As 

 is only to be expected when the fish in this region are com- 

 paratively so little known, very few of these small parasites 



Ann. & Mag. N. Hist. Ser. 7. Vol. ii, 7 



