3o6 FISHES 



the dorsal and ventral fins are elongated and nearly symmetri- 

 cal, each being preceded by a few detached short spiny rays ; 

 the colour is bluish above with five or six dark transverse 

 bands. The tail is, as in the mackerel, forked. It is a truly 

 oceanic fish found in the open oceans all over the world in 

 warmer latitudes. It is common in the Mediterranean and was 

 well known to the ancients. The habits of this fish have been 

 frequently described by travellers, but most of the accounts are 

 vitiated by the tendency of unscientific observers to attribute 

 human feelings to the lower animals, and no recent scientific 

 observations on the subject are available. That one or several 

 pilots usually accompany large sharks is an undoubted fact, 

 and they also frequently follow sailing ships ; the latter habit 

 often brings them in summer to the south coast of England, 

 where several specimens have been captured from time to time. 

 The attraction is probably similar in both cases, namely the 

 supply of food from refuse thrown overboard in the one case, 

 fragments that escape from the shark's meals in the other. 

 There is no evidence that the shark receives any benefit from 

 the pilot, any more than the lion does from the jackal ; the 

 pilot swims up to a baited hook thrown out for the shark, and 

 shows great interest in the bait, but instead of warning the 

 shark of the danger, of which he is as ignorant as his big com- 

 panion, he is evidently eager that the shark shall seize the food, 

 which usually happens, with fatal results to the shark. The 

 account of Dr. Meyen, published in 1834, which is still frequently 

 quoted, suggests that the pilot probably feeds on the shark's ex- 

 crement, but there is no evidence of this ; the stomach has 

 been found full of small fish, but probably the pilot like the 

 shark will eat any sort of animal food. 



Among the pelagic fishes of the family Stromateidae belonging 

 to the Sub-Order Percesoces, habitual association with floating 

 objects has been observed. Lirus perciformis, which has been 

 named the rudder-fish, a short deep-bodied fish with a rounded 

 snout living in the temperate North Atlantic, especially on the 

 American side, has the habit of taking up its abode within 

 floating barrels, or broken boxes, or of following floating logs. 

 The attraction in this case seems to be the barnacles with which 

 floating timber is usually covered. In 1901 a large shoal of this 

 species followed a floating log which was stranded at the Aran 



