and Labrador, with Descriptions of New Species. 249 
our A. Labradoricus, according to the shore of Davis’s Strait; 
upon which it was found. 
* Now, A. Labradoricus differs from A. variabilis in having 
one spine more on the inferior branch of the preoperculum, 
Which spine is bent forwards, and at the same time is the 
smallest of that bone. The place where it occurs, its perfect 
symmetry on both sides of the head, leaves no doubt that it 
is not an accidental variation, like the one I have mentioned 
in a young A. variabilis) Another difference consists in the 
presence of a double pair of spines above the orbits, the bind 
pair being the smallest. The occipital spines are proportion- 
ally nearer to each other than in 4. variabilis; the frontal 
space they circumscribe being thus narrower behind. "There 
exists all along the lateral line and above it, a row of hard 
plates, nearly circular, saucer-shaped, with the edge finely 
serrated. The largest, of a diameter of a line and a half, are 
near the head; they decrease in size in advancing towards 
the tail. A few are irregularly scattered on the space between 
the said row and the line of the back. 
The formula of the finsis: , 
M.o DoT AUC C 4CO.5/TL S5. VIES. 
P. 16. 
“The pectorals and ventrals appear to be longer than 
in 4. variabilis. "The space between the posterior edge of 
the dorsal and anal and the caudal is greater. sacas 
“The state of preservation of the only specimen brought 
home did not allow any further description. i 
“The same law of uniformity which prevails in the history 
of the egg and during the development of the embryo is also 
observed among young animals, especially when they belong 
to closely allied species. We know even instances where 
the young of one species assumes the form of another ge- 
nus. These facts will render difficult the attempt to refer 
to their true species young specimens, especially when sev- 
eral species occur in the same locality. Those collected 
^77 3 Proc. Bost. Soc. Nat. Hist. TII. p. 187- 
