98 DEVONIAN FOSSILS 
surface costellae had a frequency of about 24 per em. However, 
the ornamentation was finer at the umbo (specimen 27,195B). The 
beaks of some specimens are more recurved than others, but none 
are as rostrate as the genotype. 
The nearest relatives of C. polymitum are found in beds of 
similar facies and age at Killara and Lilydale, but these forms 
have not yet been described. Somewhat similar shells have been 
described by Shirley (1938, pp. 474-475) from the Baton River 
Beds of Lower Devonian age in New Zealand, but the coarse 
ornamentation on Shirley’s specimens is very different from that 
on C. polymitum. 
Genus HOSPIRIFER Schuchert, 1913 
Eospirifer easton sp. nov. 
PL ПІ, Figs. 20, 21, 23. 
Type Material. Holotype consisting of the steinkern of a dorsal 
valve on specimen 27,180, and part of the external mould of the 
same shell on specimen 27,183, the two specimens being counter- 
parts. Both are from locality G22, and Chonetes baragwanathi 
occurs on the same slab. 
Description of Holotype. Valve convex, non-plicate, large, being 
about 5-5 em. wide and the same long, the measurements being 
taken in one plane, 1.е., not following the contours of the shell. 
When the profiles are followed, the width is about 7-8 cm. and the 
length 8-8 em. Precise measurements are not possible as there is 
slight lateral crushing and all the margin is not preserved. Fold 
down middle of shell rises anterior to the umbo, rapidly gaining 
height and then gradually widening towards the anterior margin. 
The fold is about 7 mm. wide in the middle of the shell, and about 
1 em. wide at the anterior end. The fold varies from 4 to 5 mm. 
high. A narrow and low median fold is superimposed on the main 
fold from where the latter commences to a point more than half 
way down the midline of the shell. 
Palintrope well developed; interarea covered with fine trans- 
verse striae, and 2-3 to 3 mm. high. Shell considerably thickened 
about the umbo; beak small. Hingeplate strong, divided, with 
laterally elongate sockets in which to accommodate the teeth of 
the ventral valve. Hingeplate supported by strong crural bases, 
which are in the form of lamellae, slightly divergent, which reach 
a point about 8 mm. from the umbo. They lose height rapidly just 
in front of the anterior edge of the hingeplate, but rise a little and 
thicken before terminating. Between them is a broad low ridge (a 
depression in the steinkern). 
