no MARINE AND FRESHWATER FISHES 



than the usually sharp-pointed, trenchant weapons of the ordi- 

 nary Sharks, The cast of a female with its newly born litter 

 of young, similar to the one just described, is on view in the 

 Buckland Museum. The Porbeagle, or Beaumaris Shark, 

 as it is occasionally called {Lamna cornubica), No. 202, is 

 by no means unfrequent on the southern and western 

 coasts of England and Scotland ; though rarely surpassing a 

 length of six or eight feet, it possesses all the characters 

 of the most predacious species, and is armed with a very 

 formidable array of trenchant recurved teeth. Several casts 

 of this species are exhibited in the Buckland Museum, and 

 on the opening day of the Fisheries Exhibition, May 12th, 

 1883, a specimen about four feet long was exposed to view on 

 one of the stalls in the fish market. Among the more remark- 

 able members of the Shark tribe must be mentioned the 

 Fox-Shark, or Thresher {A lopecias vtdpes), No. 203, the strik- 

 ing feature in which is the enormous development of the 

 upper lobe of the tail, which is shaped like the blade of a 

 scythe, and whose length equals or exceeds that of one-half 

 of the fish's body. This formidable appendage it is 

 asserted the Fox Shark uses with terrible effect in its 

 attacks upon various of the larger Whales, with whom it is 

 said to wage a constant feud, its ally in arms being the 

 Sword-fish {Xiphias), which attacks the Whale from 

 beneath while the Sharks, leaping out of the water, fall 

 upon the Cetacean from above. In accordance with the 

 latest observations there is, however, reason to believe that it 

 is another Cetacean the Grampus (Delpkinus gladiator) that 

 is usually the aggressor and which has been mistaken for the 

 Shark. Casts of the Thresher, including that of an example 

 thirteen feet six inches long, captured in the Mackerel nets 

 off Folkestone in October 1867, may be seen in the Buckland 

 Museum. 



