SCALY-FINNED TRIBE. 343 



The Scaly-Finned Fishes, — Family Ch^etodontidje. 



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 Chcetodon belongs to a group of genera in 

 Ctisetodon. . ^ r B " . . 



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 with 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. trifasciatus, 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. fasciatus, 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 



