32 FISH GALLERY. 



the spiracle is a wide slit behind the eye. These fishes are 

 ground Sharks occurring off the coasts of Japan, Australia, &c, 

 and attaining a length of ten feet. 



In the Lamnid Sharks (family Lamnidae) the dorsal fins are 

 without spines, and the first is situated opposite to the space 

 between the pectoral and pelvic fins. There is no nictitating 

 membrane ; the gill openings are generally large ; the spiracle is 

 minute or absent. The teeth are large and cuspidate and the 

 bases are compressed antero-posteriorly, and thus differ from the 



Fig. 17. — Porbeagle Shark, Lamna cornubica. 



stout depressed bases of the teeth in the more ancient Sharks, such 

 as those already considered. The teeth are solid when completely 

 formed. The Lamnid Sharks attain to a large size and are 

 pelagic in habit. 

 Por- The Porbeagle Shark, Lamna cornubica (fig. 17) grows to ten 



beagle. f eet [ n i en gth and is occasionally caught off the British coasts ; 

 the specimen which hangs from the top of Wall-case 1 (specimen 

 40) was caught at Skye. The Mackerel Shark, Lamna spallanzanii, 

 differs but little from the Porbeagle ; the jaws of this Shark are 

 exhibited (41), and a cast of a specimen caught on the Atlantic 

 coast of North America is shown on Table 25 in the middle of the 

 other end of the Gallery. The teeth are large and lanceolate and 

 serve merely for seizing the fishes upon which these Sharks prey. 

 Great I u Carcharodon the teeth are large, erect, triangular and 



Shirk serrated along the edge (see jaws 44). The most formidable of 

 modern Sharks belong to the genus Carcharodon. A Great Blue 

 Shark or Man-eater Shark, Carcharodon rondeletii, is shown on 

 Table 25 at the other end of the Gallery, also the jaws of a 

 much larger specimen, similar to the jaws in Wall-Case 1. The 

 Great Blue Shark is known to grow to forty feet in leDgth ; 



