424 FISHES. 



of tlie saw -fish below the surface rests on somewhat 

 circumstantial evidence, the theory being, that but for 

 some forbidding presence of that nature the whale would 

 have the sense to sink to a depth where the attacks of the 

 small threshers would be of slight account. In our seas 

 this shark feeds largely on the mackerel and pilchards. 

 It occurs there all the year round, but is most in evi- 

 dence in the summer months. It is ovij)arous, depositing 

 "purses." The leaping power of this fish is extraordinary; 

 and I had on one occasion this summer two or three (one 

 caught in the nets the same evening measured 8 feet 5 

 inches from tip to tip) jumping quite their own length out 

 of the water close to my boat and not half a mile from the 

 end of Bournemouth pier. 



The largest, as well as the most innocuous, of our sharks, 

 however, is the Basking Shark, or " Sail-fish," also known 

 Basking as the " Sunfish," which occurs with us chiefly 

 Shark. on the Irish coast, growing to a length of be- 

 tween 30 and 40 feet, yet so gentle and unsuspecting as to 

 allow a noose to be slipped over its tail. In colour, this 

 huge fish is dark green to black above, white or yellow 

 beneath; above the snout is a stain of reddish brown. 

 The first dorsal fin is large, and when the fish is basking 

 at the surface is held erect like a sail. The gill-oj^enings 

 are wide and furnished with gill-rakers, the function being, 

 as in the baleen of whales, to filter the water, retaining the 

 minute organisms on which this, one of the largest of living 

 fishes, contrives to nourish itself, parallel to the largest of 

 living mammals. The eye is small and without nictitant 

 membrane ; and the spiracles are also minute. The tail, 

 the sides of which are keeled, has both lobes distinct, and 

 there is a pit at its base Attempts have been made to 

 distinguish as species more than one aberrant form of this 

 shark. 



The normal number of gill -openings in the sharks is, 



