200 



NORTHERN ZOOLOGY. 



giving place to a nacry and iridescent pearly lustre in a full light. Cheeks, opercula, and 

 hides thickly covered with nacre. 



Fins.— Br. 8; D. 15—0; P. 16 ; V. 11; A. 15; C. 19f 



The fifth and sixth rays of the dorsal are the longest, and the three first are closely applied 

 to the base of the fourth. The middle between the tip of the snout and base of the caudal 

 fin, is opposite to the ninth or tenth dorsal rays, and posterior to the attachment of the ven- 

 trals. The adipose fin is rather large, and is situated opposite to the termination of the anal : 

 it contains no rays whatever, and is not supported by interspinous bones : its base is clothed 

 with small scales. The ventrals contain eleven rather stout rays. The anal, shaped like 

 the dorsal, contains fifteen rays, of which the three first are applied to the base of the fourth, 

 and the last one is divided to its origin. The anal occupies a little more than half the space 

 between the anus and caudal. The caudal is forked and spreads widely. The scales ter- 

 minate upon it by the same outline as in the trouts, being three sides of a rectangle *. 



Dimensions. 



Inches. Lines. 



Length from tip of snout to tips of caudal 



„ „ end of central rays 



„ „ anus 



„ „ ventrals 



„ „ dorsal . . 



„ „ edge of gill-cover 



„ „ nape 



„ „ orbit . . 



,. „ nostrils • 



„ of lateral line to end of scales on 

 caudal .... 



„ iutermaxillaries, vertically 



,, labials 



19 



18 

 12 



3 

 6 

 3 

 



8 



3^ 

 10i 



4i 

 9 

 11 



Length of lower jaw 



attachment of dorsal 

 its longest rays 

 its last ditto 

 adipose fin 

 pectorals 

 ventrals . 

 attachment of anal 

 its longest ray 

 its last ditto . 

 lobes of caudal 

 its central rays 



Depth of caudal fork 



Inches. 



Lines. 



1 



3 



2 



3 



2 



7 







9 







9 



o 



9 



2 



10 



2 







2 



4 







n 



3 



8 



1 



3 



1 







Intestines 



Described from a specimen taken in Pine Island Lake, in lat. 54° N., in the winter of 1819-20. 



On opening the abdomen a multitude of caca present themselves, involved in the folds of a 

 membrane which is a production of the peritonaeum, bearing a strong resemblance to the 

 omentum of quadrupeds, and, like it, most commonly loaded with fat : it descends about half 

 way down the belly, concealing the stomach and liver, and is closely connected with the former 

 viscus by numerous vessels. A narrow spleen is attached to its right border. The alimentary 

 canal descends from the gullet in form of a wide tube five inches long, having its lining dis- 

 posed in six longitudinal folds. An inch of the upper part of the lining has a red colour and 

 glandular structure, and may be considered as belonging to the oesophagus. The remainder of 

 the tube may be termed the upper stomach : it crosses the liver by a sudden turn, and bend- 

 ing upwards terminates in an oviform bag two inches and a half long, which may be denomi- 

 nated the proper stomach. It has, from the thickness of its substance, a strong resemblance to 



* The engraver has not represented this happily in any of our plates of coregoni ; but the form that is meant may be 

 seen by turning to plate 84, or any of the other trouts. 



