55- 



SPIN1 '-FIXXEB GR O UP. 



both of which are remarkable for the extraordinary development of the appendages 

 mentioned above, some of these occurring on the fins, and others on the head and lower 

 lip. The representative of the second genus is very common at Madras. It may be 

 added that this family includes the smallest members of the suborder, which belong to 

 the genus Micropus—a name probably belonging to the swifts. These fish scarcely 

 exceed an inch and a half in length, and frequent the coral-reefs of the Pacific. ^ 



Of the three remaining and comparatively unimportant families, 

 Allied Families. ^^^ in the perc h-like section of the spiny-finned fishes, it is 

 only possible to make very brief mention. The first of these, the Nandidce, 

 differs from all the foregoing by the incompleteness or absence of the lateral 

 line ; the dentition, although feebly developed, being more or less complete, and 

 the preopercular bone having no connection with the orbit. The oblong and oval 

 body is scaled : the number of spines in the dorsal fin is nearly equal to that of 



bleerer"s plesiops (h nat. size). 



the rays ; the three-spined anal has its soft portion similar to the soft dorsal : and 

 the thoracic pelvic fins have one spine and four or five rays. The small Oriental 

 fresh- water fishes known as Nandus, Badis, etc., constitute a group of the family 

 characterised by the presence of five rays in the pelvic fins, and the absence of 

 false gills. They are common in all parts of India, some preferring ditches and 

 inundated rice-fields, while others frequent clear streams. All are carnivorous, and 

 the largest does not exceed 7 inches in length. The second group, as represented 

 by Plesiops from the Indo-Pacific coral-reefs, and Trachinops from the Australian 

 seas, although also including only small forms, are, on the other hand, marine ; and 

 are characterised by having only four rays to the pelvic fins, and by the presence 

 of false gills. In Plesiops the lower rays of the pelvic fins are elongated and split 

 at the ends; the soft dorsal and anal fins being likewise of considerable length. 

 The figured species (P. bleekeri), which attains a length of 10 inches, is from the 

 coral-islands of the South-West Pacific ; it has the lateral line broken. 



The second family (Potycentrida ) is represented only by the 

 genera Polycentrus and Monocirrhus, from the rivers on the Atlantic 



