2i8 THE CARTILAGINOUS FISHES 



reaching 15 feet in length, and, like most members of their order, 

 extremely voracious creatures. 



Another interesting shark is the Basking Shark (Cetorhinus 

 maximus). Although one of the largest of its kind, often attain- 

 ing a length of 40 feet, it is the least offensive of any. It is quiet 

 and peaceful in its ways unless it is attacked, and has a habit of 

 lying motionless on the surface of the water in calm, warm weather, 

 with the dorsal fin and upper portion of its back projecting ; it is 

 from this peculiarity it has gained its name of " Basking Shark." 

 Its food consists of small fishes and marine invertebrates, the 

 latter being strained from the water by the curious long gill-rakes 

 which fringe the gill-arches. 



The majority of the sharks are viviparous. The true Dog- 

 fishes, however, are oviparous, and the eggs are enclosed, singly, 

 in dark, horny cases, commonly called " purses." The cases are 

 oblong in shape and provided at each corner with a long, curling 

 tendril. As the female Dog-fish extrudes an egg she habitually 

 swims round a tuft of seaweed, so that the tendrils of the " purse " 

 become entangled in the fronds, securely mooring the egg-case to 

 the weed. The eggs do not hatch for several months, and the 

 young Dog-fishes make their escape from the cases through a 

 rupture at one end. 



The curious Angel-fish or Monk-fish (Rhina squatina) occupies 

 an intermediate position between the sharks and the rays. In its 

 outward appearance, and in its habits, the Angel-fish is distinctly 

 ray-like, but its internal structure has caused its inclusion in the 

 sub-order Sdachii. It is a most extraordinary-looking creature, 

 with a broad, flattened head and body, the mouth being nearly 

 terminal, instead of on the under surface as in the majority of the 

 sharks. The pectoral fins are very large and wing-like, the two 

 dorsal fins are small and spineless, and placed far back on the 

 tail, and the skin of the fish is studded with tubercles. The dis- 

 tribution of the Angel-fish is very wide ; it is frequent on the 

 shores of South Australia and Japan, on the Atlantic and Pacific 

 coasts of North America, on the European coasts, and is not 

 uncommon on the coasts of Scotland. It is often 5 feet long, is 

 viviparous, and commonly produces twenty young at a birth. 



In the Saw-fishes (Pristiophorid<z) and the True Saw-fishes 

 (Pristida) we have yet other connecting links between the active, 



