JO GIANT FISHES 



the pupil. In summer months it is not unusual for Skates 

 to come to the surface and to bask in the sunshine, and they 

 frequently leave the bottom suddenly in pursuit of prey ; 

 under such circumstances this arrangement of the eyes would 

 be of service in counteracting the sudden increase in the 

 amount of light. 



It has been shown that the Skates and Rays are protected 

 from their enemies by their general resemblance to their 

 surroundings, but, should this fail, they are provided with 

 more than one other line of defence. In the first place, there 

 are the spines with which the disc is armed, which are always 

 larger on the head, shoulders, and along the middle of the 

 back and on the tail. When threatened, they have the 

 habit of bending the snout and base of the tail towards each 

 other, making the upper surface of the back concave, and 

 then of lashing about in all directions with the spiny tail. 

 Some of the species in which the spines are particularly strong 

 have been observed to coil themselves up into a ball with the 

 spines projecting in all directions, rather after the manner of 

 a hedgehog. All Skates are also provided with electric 

 organs, situated on either side at the end of the tail, and. 

 although their pov. feeble when compared with that 



of the complicated organs of the Torpedoes, they probably 

 afford some protection. 



I the species are oviparous. The eggs are large and 

 heavily yolked, and are fertilized in the upper part of the 

 oviduct, that passage which leads from the ovary to the 

 vent. As the egg passes down the oviduct it is invested in a 

 special horny capsule or envelope, tough but not brittle, 

 which, in addition to the egg, contains a certain amount of 

 semi-fluid albuminous material similar to the " white " of a 

 hen's egg. The capsules ar- : i or 2 at a time, and 



are roughly oblong in shape, blackish or sea-green in colour, 

 and with each corner produced into a more or less stiff, pointed 

 horn. These capsules, which vary from 3 to 7 inches in length 

 rding to the species, are familiar objects of the sea-shore, 

 especially after rough weather, and are popularly known as 

 " sk:- rs ", " sailors' purses ", or " mermaids' purses ". 



They are deposited by the parent on muddy or sandy flats, 

 and, as the more rounded side of the capsule is sticky, this 



