DEVONIAN FOSSILS 109 
between the valves, similar costellation, and similar short ventral 
median septum. On the other hand, the new Species contrasts with 
C. robusta in— 
(1) The presence of growth lines and papillae. Neither of these 
structures is seen in the holotype, which is re-figured in РІ. ІП, 
Fig. 17, nor have they been seen by the writer in any other speci- 
men belonging to the species. 
(2) The small structures on each side of the ventral median 
septum are quite different from those in C. robusta. The holotype 
of the latter does not preserve this area of the valve, and so there 
is figured herewith (Pl. III, Fig. 15) a specimen of С. robusta 
glued to the same plaque as the holotype by the author of the 
species as being a further typical example of the form; it is also 
a topotype. 
(3) The costellae in C. baragwanathi occupy more space than 
those in С. robusta. The former is much bigger than the latter, 
but the two have approximately the same number of ribs. 
(4) The holotype of C. robusta is larger than is usual for that 
Species, and indeed I have seen none larger. But C. baragwanathi 
is half as big again as the holotype of C. robusta, and the other 
specimens present in the Sandy’s Creek collection show that the 
holotype of the new species is a typical specimen. 
(5) Of considerable interest and importance are the plates and 
long median septum in the interior of the dorsal valve. The 
umbonal plates are interpreted as crural bases because they occupy 
the position usual to those structures and could well fulfil their 
function. However, they are not as divergent as the crural bases 
usually are in Chonetes. 
C. baragwanathi is the most advanced of the C. robusta group 
of species, viz., C. robusta, C. kWlarensis, C. productoida, and 
Chonetes sp. from Jerusalem Creek (Gill 1945e, p. 123). 
Genus TANCREDIOPSIS Beushausen 
Tancrediopsis raricostae ( Chapman) 
Pl. II, Fig. 4; Pl. ITI, Figs. 5, 8, 11. 
Palaeoneilo raricostae Chapman 1908, Mem. Nat. Mus., Vic., No. 2, pp. 34-35, 
Pl. III, Fig. 50. 
Material for Description. A single specimen (No. 27,229A) 
from locality G 24. It is a steinkern of a right valve, and a small 
piece of the external mould (No. 27,2298, now mounted in plaster 
of paris) was obtained when clearing the fossil; this shows the 
nature of the ornamentation. 
