OF THE BRITISH ISLANDS. 187 



The Toper, or White Hound (Galens cams), No. 199, some- 

 times attains to a length of six feet, and in shape and 

 aspect much resembles the Picked Dog-fish (Acanthias 

 vulgaris\ No. 210, excepting that the defensive spines 

 stationed in front of the two dorsal fins are in this species 

 entirely wanting. The Hammer-headed Shark (Zygcena 

 mallens), No. 200, common in the Mediterranean and 

 tropical seas, is a very rare visitant to our shores, remark- 

 able for the lateral elongation of the orbital processes of the 

 skull, that communicate to the head its characteristic ham- 

 mer-like contour, and upon the extremities of which the eyes 

 are developed, the visual range of the fish by this arrangement 

 being greatly increased. The cast of a small exotic example 

 of this species, which grows to a length of ten or twelve 

 feet, will be found in the Buckland Museum. It is usually 

 described as among the most ferocious examples of the 

 Shark tribe, though authentic records seem wanting to show 

 that man has been the subject of its attacks. The Skate- 

 toothed Shark, or Smooth Hound ( Mustelus vulgaris\ No. 

 20 1, is among the smaller species, rarely exceeding a 

 length of three or four feet. In common with the Toper 

 and Picked Dog-fish, it has frequently been acclimatised in 

 the tanks of our larger aquaria. In the year 1875 a pair of 

 these fish, male and female, were captured the same night 

 in Mr. Parry Evans' Salmon Weir at Colwyn Bay, North 

 Wales, and secured by the writer for the Manchester 

 Aquarium. Soon after arriving at their destination, the 

 female gave birth to eleven young ones, which, with the 

 exception of one example which was apparently devoured by 

 the male fish, were successfully reared. The name of Skate- 

 toothed Shark has been conferred upon this fish with 

 reference to the flattened tesselated character of the teeth, 

 which more nearly resemble those of the Rays and Skates 



