5G8 ^\y. C. T. Regan on the 



II. Dorsal fin ?iiiall and spineless, or absent ; teeth minute nv aVsent ; 



no post-tt'ra]ioral ; other osteological characters of Schilhe : ver- 

 tebrse 1 0-11+41 44. {SilitranodontiiKe.) 



African Silmanodun, Parailia, Physa- 



ilia. 



III. Dorsal fin absent; teeth well developed; post-temporal present ; 

 hypocoracoids not meeting; air-bladder tubular, transverse, 

 crescent ic, curved forward on each side, the horns lying in a pair 

 of recesses open beliind, formed by the laminar parapophyses of 

 llie fourth and fifth vertebrae, by a ventral lamina which curves 

 upwards anteriorly, and by the lower limb of the supra-clei- 

 thrum ; vertebrte 11+41-47. {Ailiincft.) 



Indian Ailia, Ailichthys. 



Family 13. Clariidae. 



Naked, elongate ; gill-membranes separate, free from 

 isthmus. Dorsal fin spineless, commencing not far behind 

 head; anal long, many-rayed, nearly or quite reaching 

 caudal; pelvics, when well-developed, 6- rayed ; pectoral 

 with a spine. Head depressed ; mouth transverse, terminal ; 

 bands of villiform or granular teeth in jaws and on vomer ; 

 4 pairs of barbels, nasal, maxillary, and two mandibular. 

 Cranial roof-bones more or less expanded and laminar, the 

 pterotics appearing as a pair of plates at the sides of the 

 supraoccipital ; epiotics concealed beneath snpraoccipital ; 

 side of head with two plates, the anterior, "^ postorbital,'^ 

 attached to the frontal above and behind the orbit, the 

 posterior, " teiuporal,^' attached to the pterotic and supra- 

 cleithrum. Palatine long, rod-like; pterygoid absent; 

 mesopterygoid large, connecting the rather small metaptery- 

 goid with vomer (fig. 1, A). Post- temporal a"bsent ; supra- 

 cleithrum a plate rigidly attached to pterotic, without lower 

 limb, with a posterior process firmly united to air-bladder 

 capsule ; mesocoracoid pre sent ; hypocoracoids interlocking 

 below. Vertebrae 60 to 107 ; free preecaudals with ribs on 

 well-developed parapophyses ; complex vertebra rigidly 

 united with fifth, first and skull, by suture and by investing 

 bone ; parapophyses of fourth and fifth vcrtebrre forming 

 on each side a transverse cylinder or scmi-cylindcr with 

 terminal aperture beneath the skin ; air-bladder represented 

 by two sacs enclosed in the cylinders, connected by a 

 transverse tube from which a duct runs to the oesophagus. 



Fresh-water fishes of Africa and Asia. 



The Clariidic are a specialized family, but show relation- 

 ship to the Schilbeida?. A good ilhistrated description of 

 the head-skeleton of Clarias has been given by Schciaputiu 

 (Bull. Soc. Nat. Moscou, 1905, p. 85). 



