Classification of the Order Ostariophysi. 31 



The principal genera may be arranged thus * : — 



I. Mesethmoid firmly united to frontala ; skull depressed ; anterior 



part of air-bladder nearly divided into two, the lateral halves of 

 the capsule connected only by a narrow biidge ; no spine ; barbels 



6 or 8. {Nemachilin(e.) Nemachihis, Diphyphysa, 



Oreonectes, Lefua. 



II. Mesethmoid movably articulated with frontals ; skull compressed ; 



air-bladder undivided, the central portion of the capsule sub- 

 spherical. {Cobitidince?^ 



A. No spine ; 10 or 12 barbels ; parapophyses ankylosed with centra. 



Misgurnus, 



B. Lateral ethmoid a movable spine ; 6 or 8 barbels ; parapophyses 



distinct from centra Botia, Parabotia, Lepto- 



botia, Acanthopsis, Cobitis, Zepidocephnlicht/a/s, 

 Jerdonia, Acanthophthalmus, Leindocephalus, 

 Eucirrichthys, Apua. 



Family 4. Homalopteridae. 



Piseraaxillaries excluding maxillaries from gape; three 

 pairs of barbels or more. Pharyngeal teeth uniserial, often 

 rather numerous ; lower pharyngeals falciform ; pharyngeal 

 processes of basioccipital very small or absent ; no horny 

 pharyngeal pad. Skull depressed ; mesethmoid broad, firmly 

 united to frontals ; subtemporal fossae deep ; lateral occipital 

 foramina absent. iSuborbitals ossified and prseorbital larfe, 

 extending forward to the end of the snout, supported by an 

 anterior process of the lateral ethmoid. Cleithra dii-eclly 

 attached to epiotics, expanded below to form horizontal 

 lamina3. Air-bladder reduced, completely divided into two 

 lateral portions, each enclosed in a capsule formed by the os 

 suspensorium and the transverse process of the second vertebra • 

 each capsule with a lateral orifice beneath the skin and with 

 an extended facet for articulation with the cleithrum. 



This well-marked family includes a number of species from 

 Southern Asia, which are readily distinguished by the nume- 

 rous barbels, the subterminal or inferior mouth, the flattish 

 lower surface, and the horizontal paired tins with the anterior 

 rays simple, graduated. 



Genera : IJomaloptera, Lepturichthys f, Helgia, Balitora, 



* Cf. Vaillant, Notes Leyden Mus, xxiv. 1902, p. 133, for a synopsis 

 of the genera. 



t Lepturic.hthys, gen. no v., type Hoynahptera fimbriatum, Giiuth., 

 dillers from Homaloptera in the long slender tail, with a dorsal and 

 ventral series of plates, which are probably expansions of the nenral and 

 hajmal spines. 



