GREENLAND SHARK. 405 



be satisfactorily discovered. In swimming, the tail only is 

 used : the rest of its fins being spread out to balance it, are 

 never observed in motion but when some change of direction 

 is required." 



" To the posterior edge of the pupil of the eye is attached 

 a white vermiform substance, one or two inches in length. 

 Each extremity of it consists of two filaments, but the cen- 

 tral part is single. The sailors imagine this Shark is blind, 

 because it pays not the least attention to the presence of a 

 man ; and is, indeed, so apparently stupid, that it never 

 draws back when a blow is aimed at it with a knife or lance." 



The eyes of this Greenland Shark, with the appendages, 

 were brought home by Captain W. Scoresby, preserved in 

 spirits, and submitted to Sir David Brewster, who gave one 

 specimen to Dr. Grant. The appendage proved to be a new 

 species of parasitic animal, which Dr. Grant named Lernaa 

 elongata, and described it, adding a figure of it, in the se- 

 venth volume of the Edinburgh Journal of Science. The 

 imperfection of the vision of the fish was probably produced 

 by the various perforations made in the cornea by the tenta- 

 cula of this new species of Lernaa ; as it is by those organs 

 that these parasitic animals retain their hold and live upon 

 the fluids extracted from the animal to which they adhere. 

 This species of Lernaa is perhaps the largest known : it mea- 

 sured three inches in length. 



The genus of Sharks next in order, according to Cuvier's 

 arrangement in the Regne Animal, is that of Zygana, or 

 Hammer-headed Sharks, of which a single specimen is re- 

 corded by Messrs. C. and J. Paget, in their Sketch of the 

 Natural History of Yarmouth, page 17, to have been taken 

 there in October 1829, the head of which is now preserved 

 in the Norwich Museum. 



The specific name of the example taken, and here referred 



