6 ACANTHOPTERTGII. 



13. Dules. Brancliiostegals six. Preopercle serrated : opercle spinate. "VilTiforni teeth in jaws, vomer, 

 and palate. A single dorsal fin, deeply notched between the ninth and tenth spines : three anal spiaes. Scales 

 ctenoid and of moderate size. 



Sixth group — Theraponina. 



Branchiostegals six. Opercle spinate : preopercle serrated. Cleft of mouth somewhat oblique. Dorsal 

 fin single, but more or less notched : three anal spines. Air-vessel divided by a constriction into an anterior 

 and posterior portion. 



14. Thereupon. Teeth viUiform in jaws, deciduous on vomer and palate. 



15. Bairda. Teeth villiform in jaws, palate edentulous. Snout rather produced. 



16. Helote's. Palate edentulous, teeth in the outer row in the jaws having a small lobe on either side. 



Seventh group — Pristipomatina. 



Branchiostegals from five to seven. Preopercle serrated or entire. Mouth moderately protractile. 

 Teeth in the jaws. Three anal spines. Air-vessel destitute of any constriction. 



17. Pristvpoma. Brancliiostegals seven. Opercle with indistinct points : preopercle serrated. Cleft 

 of mouth horizontal : a median groove along the under surface of the lower jaw. Dorsal fin single, but often 

 with a deep cleft between the last two spines. 



18. Ha/palogewys. Branchiostegals six or seven. Preopercle serrated : opercle ' with short points : 

 barbel-Kke papUlse on the mandible. Villiform teeth in jaws, vomer, and palate, with an outer enlarged row in 

 the former. Spinous dorsal low, and deeply cleft : anal with three sprues. Mns covered with fine scales. 



19. Diagramma. Branchiostegals six or seven. Preopercle serrated. Mouth smaU : lips thick : pores ' 

 on the under surface of the lower jaw, but no median groove. A single dorsal fin. 



20. Lobotes. Branchiostegals sis. Upper profile of the head concave. Preopercle serrated. Lower 

 jaw the longer. A single dorsal fin. 



21. Scolopddes. Branchiostegals five. Preopercle serrated. A backwardly-directed spiue on the 

 infraorbital riag of bones : opercle with a weak spine. A single dorsal fin. 



22. Dentex. Branchiostegals six. Preorbital high, Preopercle entire. Generally strong canines. 

 More than three rows of scales on the preopercle. A single dorsal Sn. Air-vessel notched posteriorly. 



23. Synagris. Branchiostegals six. Preorbital high. Preopercle serrated, or entire. Canines, not 

 very strong, at least in the upper jaw. Three rows of scales on the preopercle. A single dorsal fin. 



24. Pentapvs. Branchiostegals six. Preorbital low. Preopercle entire. Generally strong canines. 

 Three or more rows of scales on preopercle. A single dorsal fin. 



25. Smaris. Branchiostegals six. Preopercle entire. Vomer edentulous. Mouth protractile. A single 

 dorsal fin. 



26. Odontoneetes. Branchiostegals six. Preopercle serrated. Villiform teeth in jaws, vomer, and 

 palatine^. A single dorsal fin. 



27. Gcesio. Branchiostegals six or seven. Preopercle entire or finely serrated. Palate edentulous. 

 A single dorsal fin. 



Eighth group— Gerrina. 



Branchiostegals six. Body elevated or oblong. Preopercle serrated or entire. Mouth very protractile. 

 Villiform teeth in the jaws. A single dorsal fin : three anal spines. Air-vessel simple. 



28. Batnioides. Preopercle serrated : opercle with short spines. A deeply notched dorsal fin : caudal 

 rounded. 



29. G&rres. Preopercle mostly entire. Inferior pharyngeal bones united by a suture. Dorsal fin with 

 a scaly sheath. Caudal forked. 



GeogrwpMcal distribution. The Indian PEECiDiE are almost entirely marine fishes, if we are to judge 

 from the localities where they breed, and the places in which they are most abundant. It is by no means 

 uncommon to capture specimens of Lates long distances above tidal influence, but it is unusual to find any of the 

 genera Serra/rms, Luticmus, Therapon, PrjiStvpoma, Lobotes, Batnioides, or Oerres, many miles beyond the reach of 

 the tides. The remainder of the genera (excluding Ambassis) are almost entirely marine. Amongst this last 

 genus, which is considered by several excellent ichthyologists as forming a distinct family, some are confined to 

 salt water, but the majprity are spread through the larger rivers, and tanks of the plains. 



The colours and tints in fishes vary in different waters, if for instance the latter is opaque or muddy its 

 finny inhabitants will be found darker ; whilst, on the other hand, in clear water they are brighter, and generally 

 lighter.* Age and season likewise exercise an influence in this respect. Thus the iuitarews marginatus has a 

 black lateral blotch in the young which generally, but not invariably, disappears in the adult ; the same is seen in 

 CJicetodon Vurmla, EtropVus Suratensis anjd many other fishes. In some of the Serrani, and sometimes in 



* Dr. Stark (Proc. Zool. Soc. 1833, p. 88) obsra-ved that the effect of keeping living fish in fresh water contained in vessels of 

 different colours, crested » tendency .to their assumjiig Jhg colojir of the vessej in which they were kept. In marine forms it has been 

 suggested that the depths of the ocean at which some reside may have an effect upon their colours. 



