266 J. D. OGILBY AND A. R. McCULLOCH. 
aa. Anal fin inserted nearly opposite to the second dorsal; 
spiracle minute, behind the eye; teeth in three series, 
of which the outer one only is functional; each tooth 
with a finely and evenly serrated convex edge; species 
oviparous ? Nebrius. 
aaa. Anal fin inserted wholly behind the second dorsal. 
b. Spiracle large, situated below the level of the eye. 
ce. Teeth dissimilar, those in front long, slender, and smooth, 
those on the sides small, tricuspid, and in few series; 
sides of head with a more or less interrupted series of 
dermal lobes; species ovoviviparous. Orectolobus. 
ec. All the teeth similar, small and tricuspid, arranged in 
many series; head without dermal lobes. 
d. Tail short, not more than one third longer than the head 
and trunk; species Ovoviviparous. 
e. Head strongly depressed; mouth wholly in advance of 
the eye; anal fin approximate to the caudal. 
Bracheelurus. 
ee. Head not depressed; mouth below the front of the eye; 
anal fin remote from the caudal. Heteroscyllium. 
dd. Tail long, not less than one half longer than the head 
and trunk; species oviparous. Chiloscyllium. 
bb. Spiracle large, behind the eye; teeth inserted on a flat 
Subquadrangular pair of transverse cushions; tail at 
least twice as long as the head and trunk; species 
Oviparous. Stegostoma. 
The genus Nebrius, Riippell, considered by Regan to be 
a synonym of Ginglymostoma, M. & H., has not yet been 
recorded from Australia, but from its extended distribution 
will very probably be found here later. It is therefore 
included in this key for future convenience only. 
