74 
GRAPTOLITES OF AUSTRALIA 
thecae pendent in position, later thecae becoming more 
horizontal.” He relegates Thysanograptus to the synonymy 
of Lasiograptus (senu stricto). 
Triaenograptus he places under ? Graptoloidea incertae 
sedis describing it as having a “rhabdosome circular with 
radiating branches, from which paired lateral branches are 
repeatedly produced forming trident-like structures, adjacent 
lateral branches may unite to a single branch, from which 
paired laterals may again later be developed.” 
In regard to hydroids he includes under the Order Den- 
droidea. Family Dendrograptidae, Family Callograptidae, 
Family Acanthograptidae fam. nov. for the genera AcantJio- 
graptus and Thallograptus, and the Family Ptilograptidae 
of which the only genus is Ptilograptus. As a separate 
grouping he gives genera of uncertain systematic relation- 
ships, described as primitive graptoloids or dendroids, but 
having probably by droid affinities; such are Mastiograptus 
and Cliaunograptus. A genus which has been referred to 
the Dendroidea but with uncertain relationships is Cacto- 
graptus. 
G. F. K. Naylor (159) has extended his study of grapto- 
lites in New South Wales by recording the presence of twenty- 
four Upper Ordovician species and varieties distributed 
through twenty-six localities and ten Silurian species and 
varieties in four other localities, the position of which are 
stated in teims of a grid-map covering 2,000 square miles of 
the Goulburn District, lying chiefly within the County of 
Argyle. He reaffirms his determinations of the occurrence 
of Monographts harrandei, M. cf. decipiens, M. cf. tortilis 
and 31. undiilatus, on which some doubt had been expressed 
by Thomas (141). He also suggests that the locality Tallong 
named in the title of T. S. Hall’s paper (63) was a misprint 
for Tolwong, the name appearing in the title of the second 
paper (86) on fossils from the same district. 
Subdivisions Proposed by Various Authors. 
Silurian. 
Gregory, 1903 
vide p. 39 
Chapman, 1913 
(71) 
Chapman & 
T homo's, 1935 
(136) 
Thomas & Keble, 
1933 
(126) 
Yeringian 
Melbournian 
Tanjilian 
Yeringian 
Melbournian 
Yeringian 
Melbournian 
Keilorian 
Yarravian = Melbournian 
Yeringian 
Keilorian 
