AnrHUR.—On the Brown Trout introduced into Otago. 287 
made diagrams of the heads of three sea trout (being the only ones I can 
get), two of which are at present in my possession, and one belongs to our 
Museum. They were caught in Otago harbour. 
These are placed beside the diagrams of S. fario to facilitate comparison. 
By this means some characteristic distinctions are at once apparent. In 
each head the lower jaw is rather longer than the upper. The maxillary 
does not project beyond a vertical line drawn from the posterior margin of 
orbit. The lower limb is narrower and the upper broader relatively than 
in the two heads of S. fario, and the whole bone is finer and more delicate. 
Of the gill-covers, the greatest difference is manifest in the suboperculum, 
which roughly approaches a sector of a circle in outline, its lower free 
margin being nearly semi-circular. The outline of integument on surface 
of this bone has a great similarity in the three specimens, and differs 
decidedly from that on the same bone on the trout heads. The spots on 
the gill-covers are from three to four, while in the trout they are from seven 
to eleven; while of the more general features the heads are short and 
deep, and fine at the snout, that of the Museum specimen being only one- 
fifth of the whole length of the fish. This fish measures—length, 16 in. ; 
depth, 33 in. ; head, 23 in.; and scales 16 in transverse row from adipose 
fin backwards. And lastly, these three fish have the distinct coating of 
bright silvery scales all over their bodies. The description of the head 
( S. trutta), given by Günther and Yarrell, agrees very well with the above 
three specimens. 
DESCRIPTION OF PLATE XIII. 
[Norz.—Reduced one-half from the author’s original drawings. ]- 
Salmo fario. 
Fig. 1. Fac-simile head of female trout, taken in Lee Stream, Oct., 1877; weight, 43 Ibs. 
2. Fac-simile of dried head of female trout taken in Upper Taieri, Mar. 1878; weight 
6 lbs. 6 ozs. 
{Norz.—The numbers represent the following bones: 1, pre-maxillary or inter- 
maxillary; 2, maxillary; 3, mandible; 4, operculum; 5, suboperculum; 
6, interoperculum ; 7, preoperculum. 
Salmo trutta. 
" Fac-simile head of female, 7 Ibs. weight, got in harbour, Nov. 6, 1877. 
Do. do. dried specimen, 1 lb. weight, got in Otago Harbour, March, 
1878. 
6. Hand-sketch head of specimen, Ijlbs. weight, in Otago Museum; caught at 
Otago Heads, April, 1874. 
