6 
triangular basipterygia ( bpt .) are longer than wide, and meet in the middle 
line at their attenuated apices. In their fossilised state they are pierced near 
their distal end by a few oval foramina, which may originally have been 
either pits or perforations. Each basipterygium bears at least six, perhaps 
eight, slender cartilage-rods, besides the basal piece of the long series of nearly 
square cartilages which form the clasper. The remains of the right pelvic 
tin exhibit at least twelve cartilages in this series, while the left fin shows a 
slight adjoining expansion, tapering distally, which seems to have been 
strengthened only by dermal filaments. The dorsal fin arises immediately 
behind the shoulder girdle and clearly extends continuously along the whole 
length of the back. It is supported as usual by long baseosts and compara- 
tively short axonosts, each support bearing a tapering cartilaginous ray in 
the fin-membrane. 
Subclass — Dipnoi, 
Order — SIEEN OIDEI. 
Family — CTENODONTIDJE. 
Genus — SAGENODUS, Owen, 1807. 
(Trans, Odontol. Soc., v, p. 365.) 
Gen. Char . — Body depressed, and covered with large thin scales, 
which are almost quadrate in shape but with the angles well rounded ; both 
scales and external bones destitute of a ganoine- layer. A large median 
occipital plate posteriorly, with a smaller median plate immediately adjoining 
the front margin of this element. Dental plates, above and below, triangular, 
irregularly ovate or elliptical in form, with few strong, outwardly directed 
ridges, which are more or less tuberculated or crenulated ; vomerine teeth 
resembling a single ridge of a dental plate. Dorsal and anal fins continuous 
with the caudal. 
Ohs. — Sagenodus occurs in the Carboniferous and Lower Permian 
both of Europe and North America. Fragments are not easily distinguished 
from the closely allied Carboniferous genus Ctenodus ; but the exact 
determination of the Australian specimen now described is rendered possible 
by the preservation of the greater part of the palatine dental plates. At 
