2 
g . Depressible canines very many 
(30); teeth biserial; mouth 
large, not completely clos¬ 
ing. , AEmasla, 
2$^. Front nostril with thickened 
rim forming bilobed posterior 
flap; hind nostril oval open¬ 
ing, nearly equals eye and 
surrounded by thin membrane, 
^nchelyn^sag^ 
3 
f c . Both front and hind nostrils 
equally tubular, Mu renoghls, 
Teeth mostly obtuse, molar like; only 
front nostril tubular; mouth cleft 
rather short; dorsal begins before 
gill opening. Echidna, 
Uropteryglnae . Vertical fins rudimentary 
or absent, when present terminal on 
tail; teeth rather small, pointed, sub¬ 
equal, in several rows; hind nostril 
round, with or without short tube, 
g , Tail about long as rest of 
body; snout moderate, half 
mouth cleft, which not half 
of head, Uropterygius, 
