Mackoptebous Abdomisals.- 



-FISHES.- 



-Amidass. 



151 



arc handsome small fishes, of comparatively little cco- 

 iiomio value. 



Tlie genera are — Osieoglosswn; Ischnosovia; and Hi/odon; 

 sncli species as inhabit the waters of the United States being 

 called Gold-eyes, Toothed Herrings, Moon-eyed Herrings, and 

 Shiners. 



Family XIV.— ERYTHRINOIDS {ErylhriniJn:). 



This small group, named Erythrijidcs by Valen- 

 ciennes, contains some genera whoso true alTinities 

 have not yet been ascertained by ichthyologists. The 

 lOrythrinoids have moderately thick bodies, with rounded 

 backs and bellies. Tlie upper arch of the mouth is 

 forinod by the premaxillaries, and the maxillaiios, arti- 

 culated to their extremities, are both, together with 

 I he mandible, crowded with small conical teeth. The 

 vomerine mesial line is smooth, but on each side of it 

 an arched plate of villiform teeth lines the vault of the 

 mouth. The entire cheek is covered by bony sub- 

 orbitar scales, followed by two temporal plutcs which 

 are characteristic of the famil}'. The stomach is coni- 

 cal and siphonal, and the pancreatic creca are numerous. 

 The o\'isacs do not communicate with the cavity of 

 the belly, and the air-bladder is double ; the roundish 

 anterior chamber being clothed with a thick, exterior, 

 loosely-adliering capsule, which is inserted into the 

 proecssos of the third and fourth vertebrae, but docs 

 not communicate with the labyrinth of the ear ; the 

 second chamber is cellular anteriorly', without exten- 

 .sivo partitions, but with recesses formed by longitudinal 

 and transverse bridles and folds of the interior coat. 

 A pneumatic tube leads from the second chamber to 

 tlie top of the cesophagus. They are Characini with- 

 out adipose fins. 



The genera arc — Erijllirlmis ; Macrodon; Lebiaslna; FipT- 

 hnJiiia; Urnltra; Melanura (Agassiz) ; Vussumiera; and 

 Etnuncus. 



Of these Umhra and Macrodon want cells in their 

 simpilc air-bladder. Valenciennes remarks that Enj- 

 tltrinus agrees with the Salmonoids in the structure 

 of the face ; with the Cyprinoids in the size of the 

 lateral occijiital openings ; with the Clupcoids in the 

 parioto-occipital foramina, and in the form of the 

 basilar occipito-sphenoid bone ; with the Cyprinoids 

 again in the confluence of the anterior vertebra;, and 

 in the existence of a chain of ossicles connected with 

 the first chamber of the air-bladder, but not reaching 

 to the vestibule of the ear, as in the Cyprinoids. Most 

 of the family inhabit tropical or subtropical countries. 

 Eyylhrinus cincrcus ia the " Waubeen" of Trinidad. 

 The Macrodons bear the native names of Tareira, 

 Uuavina, and Hiiimara in South America ; and one 

 sjiccies {Macrodon fcrox) is called Yarrow in the island 

 of Trinidad (Gill) ; Umbra is the llundjisch of the 

 Austriaus. 



Family XV.— ELOPIANS {Elopidw). 



This family group is distinguished from others by 

 the presence of a sublingual bono between the limbs 

 of the mandible and behind the branchiostegal mem- 



brane , also by an unusual number of branchiostcgals. 

 The mouth is like that of the Clupeoids, bordered 

 above by small premaxillaries, and flanked by loiig, 

 free maxillaries. Teeth exist on all the dentifcrous 

 bones, but so fine as to appear merely a roughness. 

 Body long and ronnded, without serratures on tlie 

 belly. Dorsal fin situated in the middle of the length. 

 At the base of the deeply-forked caudal, above and 

 below, there is a large indurated scale ; and long scaly 

 appendages are seated in the axillai of the pectorals 

 and ventrals. The head is naked, and the eyes fur- 

 nished with a waxy-looking membrane. Stomach 

 conical; numerous pyloric cffica ; air-bladder large, 

 forked anteriorly, and communicating with the diges- 

 tive caudal, but not entering the cranium. 



The genera are — Elops and Merjahps. 



These fish have a variety of local names in the 

 United States and West Indies, such as Silver- 

 fish, Eound-fish, Herrhigs, Pounders, Pond King fish, 

 Call'um, Lisa-fiancesa, Banana, Caballero, Sahallo, and 

 Savale. In the Bed Sea they are termed JIachnat ; 

 in Ilindostan, Inagore ; and in China, Chuh-Kcaou. 

 They attain a considerable size, and most of the spe- 

 cies, though sea-fish, thrive in fresh-water ponds, 

 where they fatten on the guts of fowls and other gar- 

 bage thrown to them. 



Family XVI.— AMIDANS {Amiada). 



The Mud-fish of the United States have attracted 

 much attention from ichthyologists on account of the 

 structure of their air-bladders, and M. Valenciennes 

 remarks that the single genus Amia of ten or twelve 

 species constitutes of itself a small family of fishes. 

 The air-bladder is very large, enveloping the cesophagus 

 and stomach, and communicating with the digestive 

 canal near the pharynx. It is forked anteriorly, and 

 its horns, as well as its lateral and superior parts, are 

 divided into numerous cells, which expand towards 

 their bottoms, forming bags. This congeries of cells is 

 provided with a dense net- work of delicate bloodvessels, 

 and is therefore believed to act a part in the oxygena- 

 tion of the blood. The pneumatic tube is very short, 

 but at the same time very wide, and issuing from near 

 the anterior fork of the air-bladder, enters the oesoiiha- 

 gus by an oblong cleft which has two tumid lips like 

 those of a glottis. Another characteristic of the Ami- 

 dans, is a sublingual bono like that of the Elopians. 

 The naked cranium, supratemporals, suborbitars, and 

 operculum are sculptured, but the interior of the mouth 

 is like that of a trout, except that there are no lingual 

 teeth. The ova drop into the cavity of the abdomen 

 like those of a salmon. The caudal comes farther for- 

 ward above than below. 



These fish can live for some length of time out of 

 water, and travel from one piece of water to another. 

 They have a spiral valve in the caecum, but otherwise 

 resemble the Cyprinoids in the simplicity of the intes- 

 tinal canal without ca}ca. They have been considered 

 to be Ganoids, but the latest observations are against 

 such an arrangement. 



