ADDENDA. 311 



less compressed than any of the other North American Coregoni that we have 

 seen. 



In Plate 94, f. 2, the head of a Coregonus albus is represented the size of life> 

 to show the correct forms of its different parts : in f. 2, b, the mouth is seen in 

 front, and in c, on the stretch sideways, exhibiting the depth of the intermaxillaries, 

 which is much greater than in the herring-salmons, of which reduced figures are 

 given in plate 90. 



Page 232. Hiodon chrysopsis. Plate 94, f. 3. Three views of the head, 

 full size. 



The dental surface of the vomer widens gradually towards the gullet, and the palate bones 

 have, in addition to the row of conical teeth on their edges, a small oval plate of minute teeth 

 near their middles. 



Page 285, to follow Acipenser rubicundus. 



[132.] 2. Acipenser Rupertianus. (Richardson.) Rupert 



Land Sturgeon. 



Acipenser ruthenus major. Forster, Phil. Trans., lxiii., p. 149. An. 1773. 

 Plate 97, f. 1, one- third natural size. Shields full size: a. dorsal : b. lateral : c. ventral. 



Two specimens of this sturgeon have reached me from Albany River District. 

 It is a species quite distinct from the A. transmontanus (p. 278, pi. 97, f. 2), but 

 is probably the same with the sturgeon which abounds in the Saskatchewan, and 

 has been noticed in p. 279. It ranks decidedly among the Sterletce of Brandt, 

 approaching A. Ruthenus closely in its general character. 



DESCRIPTION. 



Form more slender and the dorsal profile less elevated anteriorly than in A. transmon- 

 tanus ; the top of the head and snout are also more nearly in the same line than in that 

 species, there being no sudden convexity anterior to the orbits. The snout is slender and 

 tapers gradually to its extremity, which though narrow is not acute : its breadth at the nos- 

 trils equals half the length from thence to its tip, and its sides, instead of sloping off into a 

 thin edge as in the Columbia River sturgeon, are flattened and have a vertical height equal 

 to half the transverse breadth. The upper surface of the snout is finely granulated and 



