552 



TELEOSTEI 



of the breeding habits and development in this important family. 

 To the late J. S. Budgett we owe some very interesting observations 

 made in the Gambia on Gymnarchus niloticus} The Fish makes 

 a floating nest, emerging on three sides, over which the male 

 keeps a fierce watch ; the recently-hatched larvae are remarkable 

 for the enormous size of the yolk-sac, which hangs down, acting 

 as a sort of anchor, and for the presence of long external branchial 

 filaments, as in Selachian embryos. The Fish propels itself 

 through the water entirely by the action of its dorsal fin, forwards 

 and backwards with equal facility ; when swimming rapidly 



FIG. 332. Gymnarchus niloticus. nat. size. 



backwards, it may be seen to use the end of its tail as a feeler 

 to guide the way. Budgett has also identified, with some doubt, 

 the eggs of Hyperopisus bebe, out of which emerged embryos not 

 unlike those of some tailless Batrachians, which hung suspended 

 to rootlets of grass in swamps by means of threads of viscid 

 mucus secreted from glands on the top of the head. 



Fam. 8. Hyodontidae. Margin of the upper jaw formed by 

 the praemaxillaries and the maxillaries, the latter the more devel- 

 oped and firmly united to the end of the former. Parietal bones 

 separating the supraoccipital from the frontals ; a large hole on 

 each side of the skull, between the parietal, the squamosal, and 

 the epiotic (paroccipital), closed by a large, thin, bony plate (the 

 supratemporal), which extends over the greater part of the 

 parietal ; suboperculum and interoperculum small, the latter 

 partly hidden below the praeoperculum. Basis cranii double. 

 Jaws, palatines, pterygoids, vomer, parasphenoid, and glossohyal 

 toothed ; no pharyngeal teeth. Eibs sessile, inserted above and 

 behind well-developed parapophyses ; epineurals, no epipleurals. 

 1 Trans. Zool. Soc. xvi. 1901, p. 126. 



