380 LABYRINTHICI. 



length (the caudal fin not included), the length of the head twice 

 and throe-fourths. Lateral line interrupted. Prseorbitul serrated. 

 Eeddish-olive (in spirits) : a round blackish spot on the middle of 

 the base of the soft dorsal ; an oblong blackish blotch parallel to, 

 and below, the posterior portion of the lateral line. 

 Ceylon. 



a-i, c, d, e-h, i-l-. Adults, half-grown, and young. Ceylon. Pur- 

 chased of Mr. Cuming. 

 I. Adult : skeleton. Ceylon. Purchased of Mr. Cuming. 



Description. — The head and body are oblong, strongly compressed, 

 the greatest depth being two-fifths of the distance of the snout from 

 the base of the caudal fin. The lower profile of the head ascends in 

 nearly as oblique a line as that in which the upper one descends. 

 The cleft of the mouth is rather small, oblique, the maxiUary ex- 

 tending to the vertical from the anterior margin of the orbit ; the 

 maxillary is nearly entirely hidden below the praeorbital when the 

 mouth is closed. A narrow band of small cardiform teeth in both 

 jaws, those in front being somewhat enlarged. The lower edge of the 

 proeorbital is minutely serrated. The interorbital space is slightly 

 convex, its width, in adult specimens, being nearly equal to the dia- 

 meter of the eye, which is one-fifth of the length of the head, and 

 less than the extent of the snout. Opercles without serrature ; there 

 are, however, some very indistinct denticulations at the angle of the 

 praeoperculum. The spinous dorsal fin commences in the vertical from 

 the fourth scale of the lateral line ; the posterior spines are longer 

 than the anterior ones ; the soft dorsal is pointed, the fourth ray 

 being produced into a long filament. This and the other fins are 

 much less produced in young specimens. Caudal elongate, termi- 

 nating in an obtuse point. The anal fin commences below the fifth 

 dorsal spine ; the spines increase in length posteriorly ; the sixth 

 soft ray is the longest, and produced into a filament, like the dorsal 

 fin. Pectoral rounded, of moderate length, much shorter than the 

 head. The first ventral ray terminating in two long fUaments. 



Scales ctenoid. The lateral line is interrupted below the middle 

 of the dorsal fin. Colours as described above. 



Total length five inches. 



The accessoiy organ of the giUs is contained in a membranaceous 

 sac, transparent, semi-cartilaginous, composed of three lamellae 

 which diverge from a common centre. 



The portion of the tail which is covered by the black blotch is 

 transparent when the fish is held against the light, the air-bladder 

 extending nearly to the caudal fin. 



Sheleton. — The crown of the head is convex, with three crests of 

 moderate height ; the interorbital space is rather flat, and somewhat 

 narrower than the oi'bit ; there is a narrow groove between the 

 turbinal bones, in which the processes of the intermaxillary move. 

 The extremity of the maxillary is slightly dUated ; praeorbital longer 

 than wide, the other infraorbitals very narrow ; bottom of the 

 tympanic cavity entirely osseous. The limbs of the prwoperculum 



i 



