SCALY-FINNED TRIBE . 
343 
The Scaly-Finned Fishes, —Family CentodontidjE. 
Nearly allied to the perches, the beautiful tropical fishes, designated scaly- 
finned fishes, are so named on account of the characteristic feature of the median fins 
being more or less thickly covered with small scales. In addition to this distinctive 
feature, these fishes are characterised by the deep and compressed form of the body, 
on which the scales are either ctenoid or entire, and the continuous lateral line, 
which stops short of the tail-fin. The mouth, which is generally small, is placed 
at the extremity of the muzzle, and has a distinct lateral cleft, and the eyes are on 
the sides of the head. The small teeth are arranged in bands, and there are neither 
tusks nor incisors. The soft portion of the single dorsal fin is rather longer than 
the spinous; the anal has three or four spines; the lower rays of the pectorals 
are branched; the pelvic pair are thoracic in position, with one spine and five 
soft rays; and the scaling of the median fins causes them to pass imperceptibly 
into the body. The great majority of these curious and beautiful fishes are 
inhabitants of tropical seas, and are very generally found in the neighbourhood 
of coral-reefs; but some ascend estuaries and tidal rivers, although but a 
comparatively short distance. All are carnivorous, and of relatively small size, 
while they are but seldom used for food. The three genera of which examples are 
represented in our illustration are those in which the zebra-like coloration attains 
its most marked and striking development; and for the beauty and singularity 
of their adornment these fishes are almost unequalled. Out of a large number of 
existing genera it is to these that our attention will be chiefly directed; and it 
may be remarked that the whole of them are met with in the Indian seas. 
Extinct species of zebra - fish belonging to existing genera are found in the 
middle Eocene of Italy, among these being the Indian and Australian genus 
Toxotes. An extinct genus has been recorded from the Cretaceous of Westphalia. 
The typical genus Chcetoclon belongs to a group of genera in 
which there are no teeth on the vomers or palatine bone, while the 
spines of the dorsal fin are not separated from the soft rays by a hollow or notch, 
and there is no spine to the preopercular bone; the genus in question being 
particularly distinguished by the short or moderately long muzzle, and the 
approximately uniform length of the spines of the dorsal fin. These fishes are 
common in the tropical regions of the Atlantic and Indo-Pacific oceans, where they 
are represented by some seventy species. Nearly all are ornamented wdtli bands 
or spots; a dark, or two-coloured band, passing through the eye and then inclining 
backwards, being very characteristic. Of the species represented, C. setifer, 
ranging from the Red Sea to Polynesia, is readily recognised by the elongation of 
the fifth ray of the dorsal fin, behind the base of which is a large dark spot 
with a light rim; C. trifcisciatus, which also has a similar range, but reaches the 
coasts of India, is marked by numerous fine longitudinal stripes on the body, and 
several dark bands across the head. On the other hand, in C. fcisciatus, of the 
Indian and Malayan seas, the body-stripes are oblique, and there is a single dark 
band across the head. 
Especial interest attaches to this genus, which contains but few 
species, and differs from the last by the elongation of the muzzle into 
Ch33todon. 
Chelmon. 
