ACirENSEK (UiLPEN.STADTir. 401 



rig'lit, wliieh is one-fourth of the width of the frontal interspace between the 

 orbits. The hinder border of the orbit is vertically over the anterior edge of 

 the mouth. The diameter of the lower and larger narine is equal to that of the 

 right eye. 



The body shields in all the five rows are rather distant from each other. 

 The dorsal shields number twelve or thirteen, they have round or heart- 

 shaped bases ; the keel rises gently for half the length of the shield, and then 

 terminates abruptly, usually in a recurved hook, but sometimes in a straight 

 point, which in old individuals may be worn off. The first shield is slightly 

 the largest, and the succeeding shields become smaller and relatively shorter 

 as they approach towards the dorsal fin. There are no scutes behind the 

 dorsal fin. All the scutes are coarsely and irregularly ribbed, with the 

 ribbing confused towards the centre. 



The number of shields along the sides is different on the right and left 

 of the body, as in other species, and the number varies from twenty-four 

 to thirty-six. They have a lozenge shape, with flat keels, and are largest in 

 the middle. Bony granules occur in the interspaces between them, and 

 indicate the course of the lateral line. The ventral shields are nine to ten 

 in number, round, and elevated to a central point. 



Between the vent and anal fin there is one large shield, and between 

 the anal fin and the caudal fin there is a small shield on each side. The skin 

 between the principal rows of scutes is smooth and shining, with bony scales of 

 different sizes, more or less thickly scattered over its surface, showing a raised 

 star-shape or a round denticulated form. A few larger hooked scales form an 

 indefinite single or double row between the dorsal and lateral rows of shields. 

 A similar row of much larger scales, about eight in number, runs from the 

 region of the pectoral fin some distance towards the ventral fin. These shields 

 are much larger than the lateral shields. 



Compared with A. sclii/pa, the pectoral fins in this species are relatively 

 broader, and their length is scarcely equal to the height of the body ; a long 

 unjointed soft ray similarly succeeds the strong bony ray in both species. 

 Both lobes of the caudal fin are more strongly developed than in J. schi/pa ; 

 the lower lobe is broader, less pointed, aud is half as long as the upper lobe. 



The colour of the back is a bluish ash-grey. Below the lateral line it is 

 white. The shields are dirty white. The barbels are white with blackish 

 points. The iris is silvery. 



In the young, seven or eight inches long, the length of the snout is twice 



the diameter of the mouth ; and the snout is then thin, pointed, and much 



curved. The upper side has long keeled shields. The median ridge on the 



under side of tlie snout ends in a strong hook. The shields which support the 



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