282 Transactions. — Zoology. 
There are thus three species and a doubtful fourth with unfringed 
spiracles: from these the Purakanui specimen differs in the following 
characters :— 
(1.) From T. hebetans : 
a. In the position of the first dorsal fin; 
b. In the presence of well marked emarginations separating the 
pectoral fins from the head ; 
c. In colour. 
(2.) From T. narce : 
a. In the comparative size of the first and second dorsal fins - 
b. In the absence of a well-marked longitudinal pit at the angle of 
the mouth ; 
c. In colour. 
(8.) From T. emarginata : 
a. In the position of the first dorsal fin ; 
b. In the anterior boundary of the head being eurved instead of 
straight ; 
c. In the breadth of the disc being greater than the length ; 
d. In the tail being shorter than ihe dise $ 
e. In the absence of tubercles on the dorsal surface. 
(4.) From T. fairchildi : 
a. In the position of the first dorsal fin; 
b. In the relative size of the two dorsals ; 
c. In the more rounded form of the disc ; 
d. In the distance between the emarginations being fully six times 
the distance between the eyes, instead of the two distances 
being about equal. 
According to Günther, the most important of these characters are those 
relating to the dorsal fins, namely, the position of the first dorsal with 
regard to the pelvic fins,* and the relative size of the two dorsals. For 
instance, in T. hebetans, “ the first dorsal fin is twice as large as the second, 
and situated nearly entirely behind the root of the ventrals,” while, in 
T. narce, ** the first dorsal fin is not twice as large as the second, and only 
its anterior half is opposite to the base of the ventrals.'4 
B Dr. Günther would earn the gratitude of morphologists if he would give the weight 
of his authority toa much-needed change in the nomenclature of fins. Every one knows 
that the fins of fishes are divisible into median and paired ; the former being either dorsal, 
ventral, or caudal; the latter pectoral or pelvic. If, then, the name “ anal ” could be 
abolished, the so-called anal fins being called ventrals, and the so-called ventrals pelvics, 
a very great improvement would be effected: the authority of such a book as the 
“Catalogue of Fishes” could not fail to effect the change of names within a reasonable 
period. 
t Günther, l.c. 
