Classification of the Order Ostariophysi. 25 



Family 1. Ehamphichtliyidse. 



The genus Rhaviphichthys includes fishes with a produced 

 snout and toothless mouth, mental vent and anal fin origi- 

 nating below or in advance of the eyes. Tiie pectoral arch is 

 more primitive in structure than in any other fishes of the 

 group. The small capsule which contains the anterior 

 portion of the air-bladder has a median aperture poste- 

 riorly, and there is on each side an antero-superior opening 

 whicii receives the end of the tripvs. The vertebrae are 

 numerous (more than 140 in R. rostratus) ; the skull is very 

 similar to that of Steriiopygus, with the fontanel very large. 



Family 2. Sternarchidse. - iW-ti-V^'^f^'^y''^ 



Tlie Sternarchinse include the genera Stemarchus, Stern- 

 archogito7i, Sternarchorhamphus, and Stertmvchorhynclius. 

 In this subfamily the jaws are usually toothed, but the palate 

 is toothless. 1 have examined the skeleton in Sternarchus 

 aJUfrons, which has the skull smooth and rounded and the 

 fontanel very small ; the orbitosphenoid is paired, the two 

 bones being separately united to the parasphenoid ; the 

 vertebra3 number about 70. 



I have satisfied myself by dissection tliat the pectoral arch 

 is precisely similar in structure in Sternarchus, Sternopygus, 

 and Steatoyenys, diflfering from that of Rliamphichthys in th(j 

 smaller size of the hypocoracoid and the absence of a nieso- 

 coracoid. 



Sternopygus and Sfeatoyenys agree together and differ from 

 the IS tern arch inaj in the absence of adipose and caudal fins 

 and in the structure of the skull, the fontanel extending from 

 suprn-occipital to ethmoid, and of the moulli, a nodule of 

 cartilage intervening bstween vomer and maxillary. In 

 Sternopygus teeth are present in the jaws and on the meso- 

 pterygoias, in Steatogenys the mouth is toothless. These 

 two genera, with the allied Eigenma^inia and Hypopomus^ 

 constitute the subfamily iSternopygiucB. In Sternopygus 

 macrurus there are more than 90 vertebrie. 



Family 3, GynmotidaB. 



This family includes but a single species, Gymnotus carapo 

 {Carapus fasciatus), in most of its characters nearer to 

 Efectruphorus than to the members of the preceding group. 

 The skull approaches that of Electrophorus in general form ; 

 especially noteworthy is the curving upwards of the edges of 



