ST. THOMAS. 



The Eemora is a fish provided, as a means of attachment, 

 with an oval sucker divided into a series of vacuum chambers 

 by transverse pleats. The sucker is placed on the back of the 

 fish's head. The animal thus constantly applies to the surfaces 

 to which it attaches itself, such as the shark's skin, its back. 

 Hence the back being always less exposed to light is light- 

 coloured, whereas the belly, which is constantly outermost and 

 exposed, is of a dark chocolate colour. The familiar distribution 

 of colour existing in most other fish is thus reversed. No doubt 

 the object of the arrangement is to render the fish less con- 

 spicuous on the brown back of the shark. Were its belly light- 

 coloured as usual, the adherent fish would be visible from a 

 great distance against the dark background. The result is that 

 when the fish is seen alive it is difficult to persuade oneself at 

 first that the sucker is not on the animal's belly, and that the 

 dark exposed surface is not its back. The form of the fish, 

 which has the back flattened and the belly raised and rounded, 

 strengthens the illusion. When the fish is preserved in spirits 

 the colour becomes of a uniform chocolate and this curious 

 effect is lost. When one of these fish, a foot in length, has its 

 wet sucker applied to a table and is allowed time to lay hold, it 

 adheres so tightly that it is impossible to pull it off by a fair 

 vertical strain. 



Fishing for sharks was a constant sport on board the ship 

 when a halt was made to dredge anywhere within a hundred 

 miles or so of land in the tropics. Sharks were not met with in 

 mid-ocean. Mr. Murray* examined these sharks thus caught, 

 and reports that they all, whether obtained in the Atlantic or 

 Pacific Ocean, belonged to one widely distributed species, except- 

 ing one other kind obtained off the coasts of Japan. The 

 hammer-headed shark (Zygoma malleus) was taken by us only 

 with a net on the coasts. 



The sharks were often seen attended by one or more Pilot- 

 fish (Naucrates sp.) as well as bearing the " Suckers" attached to 

 them. I often watched with astonishment from the deck this 

 curious association of three so widely different fish as it glided 

 round the ship like a single compound organism. 



* J. Murray, "Proc. R Soc," No. 170, 1876, p. 540. 



