80 
Localities . — Old Limekilns Ridge, Hume wood, near Yass, County 
Murray ( R. Etheridge — Mining and Geological Museum) : Hatton’s Corner, 
Yass River, near Yass (shales below limestone), County Murray ( T. IE. E. 
David, JE. S. Dui — Mining and Geological Museum ; R. Etheridge, A. 
J. Shcarshg, S. R. Mori — Australian Museum) : Portion 103, Parish Warroo, 
east bank of Yass River (shales below limestone), County Murray ( C . Cullen — 
Mining and Geological Museum ; R. Etheridge — Australian Museum) : 
Derreugullen Creek, a branch of the Yass River, Parish Yass, County King 
( C . A. Siissmilch — Technical College, Sydney) : Mudgee Road, five miles 
from Wellington (C. Cullen — Mining and Geological Museum) : Two miles 
east of Pine Creek, Euchareena, Parish Trudge tt, Wellington District, County 
Wellington {J. Hook — Mining and Geological Museum). 
Tryplasma Lonsdalui, car. scalariformis, var. nov. 
(Plate XII, Figs. 2 and 3 ; PI. XIV, Fig. 4; PI. XXIV, Figs. 7, 8, and 8 a; PI. XXV, 
Figs. 1-4; PL XXVI, Figs. 8-10.) 
Observations . — In company with typical examples of T. Lonsdalei, 
we meet with other colonies possessing the same general structure as the 
latter, but which may be distinguished as follows : — 
1. Although many of the corallites have the same average diameter as 
the species in chief, there is always a certain number of others 
surpassing the maximum measurement of the latter, and varying 
from eight to ten millimetres, and even attaining fifteen, just 
previous to a bud bifurcation. This imparts to the corallum in 
general a much more robust appearance, which is quite appreciable 
to the naked eye alone. 
2. The tabulae are, however, the important factor in distinguishing this 
variety. In the first place, so far as my sections show, there are no 
clusters of closely- packed floors ; but the latter are, as a rule, far 
apart and equidistant, and, in their regularity, remind one of the 
rungs of a ladder, hence the varietal name. 
3. There is also a slight difference in the gemmation, in that the young 
corallites are united laterally for some distance before springing 
from one another ; two to four buds. 
Eistulae were present (PI. XXY, figs. 1, 2, and 3). 
In the regularity of its tabulae, this variety is akin to T. ( Acanthodes ) 
lubidus, Dybowski, T. ( Amplexus ) fortuosa (Phill.), Kayser, and T. (A.) 
borussicus, W eissermel . 
