SHARKS AND RAYS 



667 



and Rough Hound, the 

 Nurse, the Picked Dog, and 

 the Silver Dog, or Tope. 

 The Nurse and Rough 

 Hound are spotted leopards 

 of the sea, and the latter has a 

 very curious propert}-. If a 

 fresh-caught " row-hound," as 

 the fishermen pronounce the 

 name, be put in a basket or 

 boat's well with pollack and 

 other fishes, the points of con- 

 tact will be marked by dis- 

 coloration of its neighbours. 

 This is probably due to some 

 acrid and bleaching secretion 

 of the row-hound's sl^in, for 

 which some economic use 

 might possibly be found. The 

 Picked Dog, or Spur-doc;, 

 has very sharp spines in front 

 of both back-fins, and has 

 therefore to be handled by 



the fishermen very cautiously, often punishing their hands badly when entangled at night m the 

 nets. Of Smooth Hounds there are- two species or varieties, between which there is some 

 confusion, and in one at any rate there are interesting anatomical peculiarities in the unborn 

 fish (like many other sharks and dog-fishes, the smooth hound bears living young instead of 

 depositing eggs), any account of which would obviously be out of place in so short a description. 

 Generally speaking, then, the sharks are cartilaginous fishes, having the upper lobe of the 

 tail larger than the lower, a shovel-shaped snout, and the crescent-shaped mouth beneath the 

 head. ^Another peculiar feature of the group is the presence of breathing-spiracles behmd 



the eyes ; while the latter 



l_Milfird-«n-St, 



Photo b^ W. Saville-Kmt, F.Z.S.] 



ocellated dog-fish 



So called from the presence of the eye-like spots on the body, t-iuo of which can be seen abo-ve the 



breast-fins 



Photo by A. S. Rudland &• Sons 



INDIAN STING-RAY 



The tail is armed -with a foiuerful foison-sfine 



have a manner of blinking 

 not found in other fishes. Of 

 the teeth, which diff'er in 

 structure from those of other 

 kinds of fishes, there are 

 several rows. The gill-open- 

 ings are lateral, and usually 

 number five, though one 

 species has six and another 

 seven. With the exception 

 of the aforc-mcntioned BasK- 

 ING-SHARK and the PORT 

 Jackson Shark, which the 

 writer met with in Australia, 

 they are all more or less 

 dangerous ; and when of in- 

 sufficient size to be harmful 

 to man, do great damage 

 among the lines and nets of 

 the fishermen, Indeed, the 



