Zoology."] 



NATURAL HISTORY OF VICTORIA. 



[Fishes. 



Plate 44, Fig. 1. 



THERSITES ATUN (Cuv.). 

 The Barracouta. 



[Genus THERSITES (Cuv. and Val.). (Sub-kingd. Vertebrata. Class Pisces. Sub-class 

 Teleostea. Order Acanthopterygia. Fam. Scomberidse.) 



Gen. Char. — Body long, slender ; mouth deeply cleft ; dorsals continuous ; spines of 

 moderate size ; 2 to 6 finlets behind the dorsal and anal fins ; greater part of body naked ; no 

 corset ; no keel on tail ; 7 branchiostegals ; pyloric appendages moderate ; an air-bladder. 

 Teeth on the edges of the jaws of moderate size, conical, compressed, pointed, but a few very 

 large on the intermaxillary bones.] 



Description. — Body a little deeper than twice the height of dorsal fin, and 

 rather more than one-eighth of total length, thickness about two-thirds of depth ; 

 head compressed, pointed, flat above, with straight profile and vertical sides, twice 

 and one-eighth longer than high; lower jaw longer than upper one; length of head 

 about four and a half in total length ; mouth slit so that the slightly dilated end of 

 the maxillary reaches to under anterior edge of orbit ; eye about midway between 

 tip of snout and edge of gill- cover, and near the upper edge of cheek. Lateral line 

 with anterior part straight and near the dorsal until opposite 15th ray, then descend- 

 ing abruptly to near middle and continuing to tail with several large undulations. 

 Fins: 1st dorsal, rays, 20; 2nd dorsal, 1 spinous and 10 soft; anal, 1 spinous and 

 10 soft; ventral, I spinous and 5 soft; 6 finlets above and below. Teeth: about 

 26 to 30 subequal, sharp, conical teeth on each side of upper jaw, the anterior smaller 

 and not quite reaching the tip of the snout ; with a row of fewer and larger ones in 

 lower jaw ; a median group of 4 or 5 large, strong, recurved, pointed teeth, six or 

 eight times longer than the others, in the middle of the upper jaw, within the dentary 

 edges ; a row of about 7 very small equal teeth on each palate-bone. Color : back 

 and top of head purplish-black ; color and lustre of cheeks and rest of body and 

 belly uniformly like polished lead; upper part of gill-cover darker; iris, pale golden- 

 yellow ; anterior dorsal fin with the rays whitish-yellow, the basal and anterior part 

 of each membranous portion transparent and colorless, the posterior and upper por- 

 tion blackish; posterior dorsal and finlets dirty -yellowish; pectoral and caudal fins 

 dirty-brown, the middle of the caudal silvery ; anal and ventral dirty-whitish. 



The detailed measurements are as under : — 



Measurements. 







Approximate 



Proportional 



Measurements. 





(A) 



(B) 



(A) (B) 





ft. ins. lines. 



ins. lines. 







Length from snout* to distal end of middle of caudal 



3 5 3 



10 



100 



100 



„ of caudal to middle 



1 1 



6 



3 



5 



„ of caudal to end of lobes 



5 



1 5 



12 



14 



„ from snout to anterior edge of orbit 



3 9 



1 



9 



5 



„ of orbit 



1 1 



6 



3 



5 



„ of head from snout to end of operculum 



8 7 



2 5 



21 



24 



* The snout measurements are from the tip of upper jaw and not from the longer lower jaw. 



[ 19 ] 



