288 Dr. A. Giinther on Additions to the British Fauna. 



canine and next premolar one-third the width of the canine ; 

 second premolar half the length of the canine, first a little 

 longei', both triangular and single-rooted; third premolar as 

 long as the canine, or one-third longer than the next molar, 

 double-rooted, and triangular. First three molars quadrate, 

 with two blunt tubercles on outer and two on inner edge; 

 fourth or last molar smallest, triangular, with one tubercle be- 

 hind and two in front. The molars and second and third pre- 

 molars are in continuous contact. Lower jaw : all the teeth in 

 continuous series without interval ; incisors long, nearly hori- 

 zontal, sharp-pointed; first three premolars small, short, and 

 obtuse, the antero-posterior extent of the first greatest, third 

 least, but all of one height ; fourth premolar twice the height of 

 the others, triangular, with a slight lobe at back of base ; first 

 molar with anterior half forming a conical lobe nearly twice the 

 height of the last premolar and of the rest of the molars ; pos- 

 terior half bitubercular, and only as high as the others, which 

 are all quadritubercular, except the small hind one, which is 

 tritubercular. 



inches, lines. 



Length of head 1 8 



„ from snout to base of tail . . 5 4 



„ of tail 6 5 



„ of ear 9 



„ of fore foot 9 



„ of hind foot 1 Oi 



„ of nasal bones 6^ 



„ of frontal bones 7 



EXPLANATION OF PLATE VL 



Fig. 1 represents the male, half the natural size. 



Fiffs. 2, Fore foot, and 3, hind foot, twice the natural size. 



Figs. 4, Upper, and 6, lower jaw, three times the natural size. 



XXX VIL — Additions to the British Fauna. 

 By Dr. Albert Gijnther, F.R.S. 



[Plate v.] 



Although we are very well acquainted with the marine fishes 

 inhabiting the shores of Great Britain and Ireland, our know- 

 ledge of the pelagic and deep-sea forms is extremely scanty. 

 Of the Dealfish {Trachypterus arcticus), a fish by no means un- 

 common in the northern and eastern seas of Scotland, I have 

 never seen a British example in a good state of preservation. 

 Now and then, after the gales of the vernal equinox, a mutilated 

 specimen of the Ribbonfish {Regalecus Banksii) is drifted ashore. 



