104 ACANTHOPTERYGII. 



Genus V. — Auxis, Cuv. and Val. 



Branchiostegals seven : pseudobranchice present. Body oblong and somewhat 

 elongated. Cleft of mouth deep. Small teeth in the jaws, but vomer and palatine 

 bones toothless. Tivo dorsal fins with a long space between them, the spines of 

 the first wealc. Seven to nine finlets behind the second dorsal and anal. Scales forming 

 a corselet in the anterior portion of the body. Lateral-line unarmed : a longitudinal 

 Jceel along the free portion of the tail. Air-bladder absent. Pyloric appendages 

 dendritical. 



Geographical distribution. — From, the German and Atlantic to the Indian 

 Ocean ; likewise in the Mediterranean. 



Auxis rochei, Plate XXXIX, fig. 1. 



Scomber tazo (Commers.), Lacepede, iii, p. 9. 



Scomber rochei, Risso, Ich. Nice, 1810, p. 165. 



Scomber bisus, Rafin. 1810, p. 45, t. ii, f. 1. 



Thynnus rocheanus, Risso, Enr. Merid. iii, p. 417. 



Auxis vulgaris, Cnv. and Yal. viii, p. 139, pi. ccxvi ; Yarrell, Brit. Fishes, 

 (Ed. 2), i, p. 160, c. fig. (Ed. 3), ii, p. 224 (not figure) ; Cuv. Regne Anim. Illus. 

 Poiss. pi. xlviii, f. 1 ; Swainson, Fishes, ii, p. 238 ; Lowe, Proc. Zool. Soc. 1850, 

 p. 248. 



Auxis taso, Cuv. and Val. viii, p. 146. 



Thynnus brachypterus, Yarrell (Ed. 3) ii, p. 219 (figure, not description). 



Auxis bisus, C.Bonap. Catal. Xo. 679; White, Catal. Brit. Fish. p. 32; 

 Moreau, ii, p. 415. 



Auxis thynnoides, Bleeker, Ternate, v, p. 301. 



Auxis rochei, Giinther, Catal. ii, p. 369 ; Canestr. Fauna Ital. p. 103 ; Xilss. 

 CEfv. Sven. Yet. Akad. Forh. 1864, p. 500, t. vi ; Steind. Ich. Span. u. Port. 1868, 

 p. 10 ; Winther, Prod. Ich. Dan. Mar. p. 14. 



Plain bonito, Couch, Fish. Brit. Isles, ii, p. 105, pi. lxxxvi. 



B. vii, D. 10-11/11-12-fYIII-IX, P. 21-22, Y. 1/5, A. 11-12+YII, C. 24, 



Yert. 39. 



Length of head 4^ to 4-|-, of lobe of caudal fin 9, height of body 4| (to 6 in 

 the young) iu the total length between the end of the snout and the centre of the 

 base of the caudal fin. Eye — with narrow adipose lids, the anterior of which 

 overlaps the posterior one inferiorly : diameter of eye 1/4 to 2/9 of the length of 

 the head, 3/4 to 1 diameter from the end of the snout, and the same distance 

 apart. Jaws of about the same length anteriorly, or the lower slightly the longer : 

 the posterior extremity of the maxilla reaches to beneath the middle of the eye. 

 Teeth — rather small in the jaws, absent from the tongue and palatine bones. 

 Fins — first dorsal of a triangular form, it commences above the origin of the 

 pectoral, the highest ray equalling the length of the latter fin : a considerable 

 interspace exists between the two fins : second dorsal low, finlets small. Yentrals 

 situated beneath the base of the pectoral. Anal commences on a vertical line 

 beneath the first dorsal finlet. Caudal deeply lobed. Air -bladder — absent. 

 Stomach elongated into a long and pointed ccecal portion, as shown in the figure 

 (plate xxxix). Scales — form a corselet over the chest, and prolonged posteriorly 

 in the vicinity of the dorsal, pectoral, and ventral fins, this is not distinct in the 

 very young. Median and lateral keels near the base of the caudal fin well 

 developed. Colours — bluish superiorly, becoming silvery white on the sides and 

 beneath, in some examples the back being indistinctly marbled : the corselet is 

 slightly darker than the body posterior to it. Fins gray, the anal having a 

 yellowish tinge. 



