96 
Eoorthis platystrophoides, Chapman sp. 
Orthis lleviensis, Etheridge fil., Chapman, 1904, Rec. Geol. Surv. Viet., 
vol. I., pt. 3, p. 224$, pi. XXI., fig. 4. Plectorthis 'platystrophoides, Chapman, 
1911, Proc. It. Soi. Viet., vol. XXIII. (N.S.), pt. II., p. 311, pt. LIX., 
figs. 14, 15 ; pi. LX., fig. 24. 
Observations. —A further examination of this specimen by means of wax 
squeezes shows that Etheridge’s species differs in having a distinctly flexed 
type of valve, whilst ours is evenly and strongly convex. It agrees in all 
the preserved characters with the form Eoorthis (Plectorthis) platystrophoides 
described from the Upper Cambrian of theDolodrook River, N.E. Gippsland. 
The riblets are strong, about sixteen in number, and wdth occasional finer 
ones in the interspaces. 
The occurrence of the above species in the Heathcote series adds another 
link to its connexion with the Mount Wellington L T pper Cambrian, Agnostus 
australiensis having been previously recorded from the Heathcote fauna. 
Pam. Orthpcle. 
Genus Hebertella, Hall and Clarke. 
Hebertella raristriata, Chapman. Plate VI., fig. 12. 
Orthis ( Hebertella ) raristriata, Chapman, 1904, Rec. Geol. Surv. Viet., 
vol. I., pt. 3, p. 224, pi. XXI., figs. 7, la. 
In this species the area is high, reminding one of Clitambonites, but the 
internal structure resembles that of Hebertella. The figure given in 1904 
requires some correction, the cardinal extremities being too produced ; they 
are in reality more rounded, giving a subquadrate outline to the shell. 
Xo. 7786 is a cast of a brachial valve of what appears to be the same 
species, and this shows the Or this-like character fairly well. 
Fam. Strophomexidje. 
Genus Eostrophomena, Walcott. 
Eostrophomexa skeatsi, sp. nov. Plate VI., fig. 13. 
Description. —The following is founded on a cast and mould of a ventral 
valve :—- 
Shell of moderate size ; nearly semicircular in outline ; cardinal line 
straight. Ventral valve moderately convex, slightly depressed near the cardinal 
extremities, and at the middle of the anterior margin. Cardinal process 
prominent and subacute. Surface of valve ornamented with about 
28 main riblets, with finer intermediate ones, and these are crossed by 
undulating lines of growth of a tegulate character. 
Dimensions. —Length, 9 mm. ; width, 14 mm. ; greatest height of ventral 
valve, 2 mm. 
This fine example (cast and mould) is named after its discoverer, Prof. 
E. W. Skeats, D.Sc. 
Relationships. —In general shape and proportion of riblets the above 
species resembles “ Leptcena 55 plicifera of James Hall 1 , which occurs at Chazy, 
Clinton Co., New York, and is of Arenig age. It differs in the absence of the 
concentric tegulate ornament. 
2 Pal., N. York, vol. I. 1848, p. 19, pi. IV.(bis), fig. la, b. 
