ICHTHYOLOGY. 



245 



Classifica- true Trouts are found. They are inhabitants of fresh water, 

 tion — Ma- and are named " Trouts" by the settlers of New Zealand 

 lacopten. ^^^^i^ Australia. As an article of food they are softer and 

 ^^^V*"^ more oily than the northern Salmonoids. 



Family IV.— SALMONID^, Mull. 



Scaly fishes, with an adipose fin. Upper half of the orifice of 

 the mouth formed by the pre-maxillaries and mamillaries ; numerous 

 branchiostegals. A large, simple air-bladder, without contractions; 

 supplementary branchia', and numerous pyloric ca^ca. They pos- 

 sess most of the characters of a Tlupeoid that has not the acute 

 and denticulated belly. Their teeth are often absent, or small ; often 

 all the pharyngeal bones are armed with them ; they are conical 

 and in one row, and when they exist on the jaws and palatines 

 the tongue also is furnished with teeth. The distribution of the 

 vomerine teeth furnishes M. Valenciennes with generic characters 

 for the subdivision of this most important but diflScult family. 



(A.) 



Genus I. Salmo, Valenc. A few teeth at the end of the 

 Tomer, but no prolonged row on the mesial line. Body fusiform. 

 Head moderately large ; throat well armed, often wide ; pre-maxil- 

 laries short, and rather on the sides of the mouth than across its 

 upper edge; maxillaries articulated to the ends of the pre-maxil- 

 laries, and not compound ; mandible strong, often with the sym- 

 physis rising into a small tubercle, but in some species the tubercle is 

 much developed. Strong conical teeth on the jaws ; a small group 

 at the end of the vomer ; one row on the palatines, entopterygoids, 

 and on each side of the tongue ; some have two rows on the tongue. 

 An adipose fin on the tail. Thin small scales covering the body. 

 A short intestinal canal ; a siphonal stomach ; ova, when detached 

 from the ovary, falling into the cavity of the abdomen before they 

 are excluded in spawning. A large air-bladder, simple, with thin 

 coats, and opening anteriorly into the pharynx, almost directly or 

 without the intervention of an air-tube. With the exception of 

 the peculiarity of the vomerine dentition, many of these characters 

 are common also to the two genera which immediately follow. 

 Twenty-five species. 



Genus II. Pakio, Valenc. Salmons with a single mesial line 

 of teeth running down the vomer. Four species. 



Genus III. S.vlar, Valenc. Vomer armed with two rows 

 of teeth, without any remarkable group on the chevron of the 

 vomer, as in the preceding two genera. Eight species, besides 

 about twelve doubtful ones hitherto imperfectly described. 



Genus IV. Osmerus, Cuv. Pre-maxillary teeth small and 

 hooked ; vomerine teeth big, conical, and so far forward that they 

 appear to belong to the jaws ; a row on the outer edge of the pala- 

 tines, and one on the internal border of the entopterygoid ; big 

 teeth also on the tongue. In other respects the Spirlings resemble 

 the other Salmonid<R, They have a small adipose tin ; ventrals situ- 

 ated under the anterior rays of the dorsal. Gill-openings widely 

 cleft; air-bladder having within silvery walls, and communicating 

 with the upper part of the oesophagus. Four species. 



Genus V. Mallotus, Cuv. Jlouth rather less widely cleft than 

 that of Osmerus, armed with very small, slender, or conical teeth 

 in a single row on the jaws ; more numerous on the palatines and 

 vomer; small teeth also on the tongue. Eiglit branchiostegals. In- 

 testines of the Trouts. One species. 



Genus VI. Argentina, Cuv. Salmonidm, in having an adipose 

 fin, and the upper half of the orifice of the mouth formed by the 

 very short pre-maxillaries and the maxillaries. Mouth small ; no 

 teeth on the jaws ; on the chevron of the vomer a curved band of 

 uniform teeth, prolonged on each side by a dental stripe on the 

 palatines; lingual teeth of variable size in different species. Gill- 

 openings wide ; branchiostegals six. Stomach moderately large, 

 caecal ; numerous short pyloric ca-ca ; ova fttUing into the abdominal 

 cavity as in the Salmons. Air-bladder covered by a coat of silvery 

 fibres, which tear off, and is used in the fabrication of artificial 

 pearls. Four species. 



Genus VII. Thymalus, Cuv. Mouth small, the orifice horizon- 

 tal under the snout ; teeth small, conicul, uniserial on the jaws, 

 chevron of the vomer and fore part of the palatines. Intestines 

 like those of Salar. Air-bladder large, communicating with the 

 oesophagus by a very small tube. The disposition of the scales 

 under the throat is peculiar in some species. Eight species. 



Genus Vlll. Coreoonus, Cuv. Pre-maxillaries crossing the 

 upper part of the mouth, thin, and of variable depth ; maxillaries 

 on the sides of the njouth also thin and attached to the ends of the 

 pre-maxillaries, generally of an oval or oblong form. Teeth small or 

 none. Dorsal fin farther forward thun the ventrals. Forty 

 species. 



Agassiz retains the name of Corcgonns for the species which Classifica- 

 have the mandible shorter than the upper jaw ; and gives the name tion — Ma- 

 of Argyrosomus to those which have it longer. lacopteri. 



Genus IX. Stenodus, Rich. Pre-niaxillarics crossing the "^—v^.-—^ 

 upper part of the mouth, giving a truncated appearance to the 

 snout, each armed by a narrow linear-lanceolate band of small 

 raduliform teeth ; maxillaries articulated to the palatine bones, 

 long and broadish, with a posterior, ovate, accessory piece as in the 

 Coregoni, and forming the sides of the mouth ; toothless ; vomerine 

 teeth in a transversely oval disk on the chevron (but not down the 

 mesial line), uniting with the crescentic bands of teeth of the same 

 kind on the palatines. These palatine bands have the hollow of 

 the crescent facing the sides of the mouth, and taper to a point 

 posteriorly. On the tongue, the teeth are rather coarser, and cover 

 its surface. Mandible rather shorter than the upper jaw, the part 

 opposed to the pre-maxillaries transverse with a knob at the sym- 

 physis, and armed there by a very narrow band of villiform or 

 raduliform teeth ; limbs of the bone longitudinal, with rather acute 

 perfectly toothless edges. The whole orifice of the mouth is nearly 

 quadrangular. In general aspect the Stenodus rather resembles a 

 Coregonus than a Salmon, but bears no strong likeness to either. 

 The ventrals are under the anterior part of the dorsal, and the adi- 

 pose fin corresponds to the posterior half of the anal, which com- 

 mences with the last third of the fish, caudal included, and does 

 occupy above a ninth of the entire length of the fish. Branchio- 

 stegals nine to eleven, often one more in number on the left side. 

 Stomach hut slightly caecal, the upward turn which ends in the 

 pylorus being short, with the oesophagus longitudinally folded 

 within. Pyloric ca^ca numerous, and crowded for an inch below 

 the pylorus, but after the insertion of the gall-duct confined to one 

 side of the intestinal tube; lower part of the gut furnished with 

 valvulae conniventes. Air-bladder communicating with the oeso- 

 phagus by a wide tube. Only one species known, the Stenodus 

 Mackenzii, Richardson (Backus Voyage down the Great Fish liiver in 

 1834 and 1835, p. 521). 



(B.) 



M. Valenciennes makes a second division of the Salmonoid fishes 

 by grouping together those in which the sub-orbitar scale bones are 

 large, and conceal almost the whole, or at least a great part, of the 

 ■interval between the orbit and the ascending limb of the preoper- 

 culum. This division includes the Charicini and Scopclince of 

 Miiller; but from the former, M. Valenciennes separates his ^rythri^ 



Family V.— CHAUACINID^. 



Ckaracini, J. Miill. Malacopterygian fishes with abdominal 

 ventrals ; adipose fin ; scaly bodies ; scaleless head ; no accessory 

 branchia; ; upper half of the orifice of the mouth formed by the 

 pre-maxillaries and maxillaries; villiform pharyngeal teeth above 

 and below ; caecal stomach ; numerous pancreatic caeca. Air- 

 bladder divided by a transverse strangulation into two, and con- 

 nected with the acoustic organs by a chain of ossicles as in the 

 GyprinidcB and Siluridoe. Branchiostegals four or five ; "numerous 

 pancreatic cieca. South American or African fluviatile fif^h. 



M. Miiller includes Erythrinus and Macrodon among his Characiniy 

 but these fish want the adipose fin of the Salmon family, and are 

 placed by M. Agassiz near the C'lupeidcB. M. Miiller's genera 

 C'atoprion, MyUles, Mt/leus, Serrasalmus, Pyyocentrus, and PugopristiSy 

 have the belly serrated. The other genera are Anodus (Curimatu$ 

 Valenc), Hemiodus, Xiphostoma, Xiphoramphusj JIiidroLijcus, Anosto- 

 mus, Leporinus^ Schizodon, Chilodus, Hydrocyon^ Cilharinus, Piabuca^ 

 (including ScMsodon, Valenc), GasteropelecuSy Epicyrtus, Raphi- 

 odon, Pacit (Prochilodus, Agass.), Disiichodus^ Exodon, Salminus, 

 Brycouy Chalceus, Alestes, Tetragonopterus, 



ANALYTICAL TABLE OP THE CHARAClNIDuE (Dum.) 



m ^u f Anodus, M. ) , 



Teeth, none { ^, xr t 1. 



' [ CUKIMATUS, V. J 



Teeth, none on the tongue, present elsewhere in the mouth. 

 Teeth elsewhere uniserial. 



Pre-maxillary teeth stronger, tricuspid,.. G AST ROPEhECVS 14. 

 Pre-maxillary teeth stronger, conical with canines. 



Bdbj rounded EPICYRTUS 3. 



Belhj keeled I J^''"''""'^; **• 1 29, 



•^ \ Cynodon, v. J 



Pre-maxillary teeth not stouter. 

 Dorsal opposed to the ventrals. 



Pre-maxillary teeth wide, entire Leporinus 2. 



Pre-maxillary teeth fissured | Piabuca, part. 1 g 



•' [ SCUISTODUN, M. J 



