a new species Jrotri the Aixtic Seas. 149 



Greenland shark," (he says,) " is attached a white vermiform 

 substance one or two inches in length. Each extremity of it 

 consists of two filaments ; but the central part is single." Two 

 specimens of this remarkable parasite, preserved in spirits 

 along with the eyes of the shark to which they adhered, were 

 brought by him some years ago from the Arctic Seas, and 

 presented to Dr Brewster, then engaged in investigating the 

 structure and functions of the organ of vision, who has kindly 

 favoured me with the larger of the two specimens, nearly 

 three inches long, and probably the largest LerncBa hitherto 

 met with. From the corrugated appearance of the tentacula, 

 and the firm texture of the whole body, this specimen appears 

 to have contracted by the long action of the spirits. In its pre- 

 sent state the dimensions of its parts are : — 



It has a straight, lengthened, and ^slender form, without 

 any lateral prolongations or branchial appendices. Its sur- 

 face is naked, smooth, glistening, and of a pale yellowish 

 white colour ; and it has a pretty firm cartilaginous consist- 

 ence, probably increased in the present instance by the ac- 

 tion of the spirits. It consists of two long cylindrical ten- 

 tacula (a, 6,) Plate II. Fig. 5, by the extremities of which 

 it adheres to the outer surface of the cornea of the shark; 

 a very distinct depressed head, (c, d,) with four antennae, 

 and two hooks at the sides of the mouth ; a subconical bodi/, 

 (d, e,) tapering above towards the head, and terminated be- 

 low by a broad base, in the middle of which are two thick 

 pendent labia concealing the anus (e ;) and two long, thick, 

 cylindrical ovaria, (f, p.) The tentacula arise from the sides 

 of the lower surface of the head, and appear a little compressed 

 and contracted at their origin, (h*) From this part they are 



