Classiyicalion of the Order Osiariophi/si', 575 



small, few-rayed ; anal sliort or long ; pelvics 6-rayed, below 

 the d(irsal. Head depressed; nostrils remote, without 

 barbel; villilnnu teeth in tiie jaws; palate toothless. 

 Palatine rod like ; mcsopterygoid, Mhen present, small, 

 attaihed to lateral ethmoid; operculum reduced, scarcely 

 larger than a brancliiostegal ray, l)ut attached anteriorly to 

 the interoperculum. Skull depressed, the pterotics with 

 strong lateral laminar ]M'ojections. No post-temporal ; 

 sn|)ra-eh'i thrum forked, the lower limb slender, running to 

 basioci'ipital, the u[)per extending nearly to the middle of 

 tlie supra"cei[)it;d ; no mesocoracoid ; hypocoracoids inter- 

 locking below. ^'erteh^ie 34 to 75 (10 + 24-65), strongly 

 cum[)ressc(l, with laminar ueural and h?emal spines and 

 with a series of horizontal lateral processes ai'ising on each 

 side from the middle of the centra ; free praecaudal vertebrte 

 without j)at apophyses, with sessile ribs ; fifth vertebra rather 

 long, rigidly united with complex, their neural spines 

 forming a low ridge of bone with thickened dorsal edge 

 wliich joins the supraoccipital anteriorh^ ; parapophysis of 

 tifth vertebra a very strong process ; parapophysis of fourth 

 a lamina, united posteriorly to the base of the fifth, anteriorly 

 decurved and united to the stem of the supra-clcithrum. 

 Air-bladder large, free, partly constricted into two lateral 

 portions. 



South -American fresh-water fishes. 



Bunocep/iulus, Bu/iocep/ia/ichi/njs and Dysichthys have a 

 short tail, anal 5- to 9 rayed, and about 24 caudal vertebrie. 

 Platystacus (Aspredo) has a long tail, anal 50- to 60-rayed, 

 and 60 or more caudal vertebrae. 



Family 22. Callichthyidse. 



Body armoured with two series of overlapping bony 

 laminte on each side. Gill-membranes broadly united to 

 isthmus. Dorsal fin anterior ; adipose tin with a spine ; 

 anal short; pelvics below the dorsal. Mouth small, ter- 

 minal; prsemaxillaries small, movably attached to mesetli- 

 nioid ; rami of lower jaw slender; jaws with or without 

 feeijle teeth ; palate toothless ; one or two pairs of maxillary 

 barrels. Palatine articulating with anterior end of lateral 

 ethmoid; pterygoid and mesopterygoid absent; anterior 

 end of metapterygoid connected, with lateral ethmoid and 

 palatine by a ligament. Bones of cranial roof more or 

 less expanded and plate-like; suborbitals well-ossified, with 

 an inner shelf; operculum large. Post-temporal absent; 

 supra-cleithrum a large plate ankylosed with the pterotie, 

 connected with sphenotic and supra-occipital above, prootic 



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