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 
longer, 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 5 cciiasyesiin cen ] 8 
», from snout to base of tail .. 5 4 
5). MO Shs ck ke 6 5 
ag: WEE wh «ky be ee 9 
ot OR CO TOE Ss ca ee a 0 9 
a OL TE OI co ee ears ] 04 
ps OR AGRE Hones Ps ye 0 63 
3 . Of frontal bones v6 66 660s 0 7 
EXPLANATION OF PLATE VI. 
Fig. | represents the male, half the natural size. 
Figs. 2, Fore foot, and 3, hind foot, twice the natural size. 
Figs. 4, Upper, and 5, lower jaw, three times the natural size. 
XXX VII.— Additions to the British Fauna. 
By Dr. Abert Guntuer, 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, 
