98 
Observations. —-Although the history of Grammysia is assumed to commence 
in the Llandovery, the above species seems to naturally fall into this genus. 
The folded shell-surface, with interdigitating rugae, are characters not seen in 
Modiolopsis “sensu stricto,” to which genus it might otherwise belong. A 
similar form of shell is “ Modiolopsis ” parallela, J. Hall * 1 , of the Trenton 
Limestone, New York State, but this differs chiefly in the truncated posterior 
and less pronounced rugae. Although this fossil has the appearance of a true 
pelecypod, we bear in mind that some ceratiocarids described by Mansuy as 
Sinocaris 2 approach it in outline and ornament. The crustacean genus, 
however, is of Silurian age, and the superficial aspect is more depressed. 
Class TRILOBITA. 
Fam. Agnostid^s. 
Genus Agnostus, Brongniart. 
Agnostus australiensis, Chapman. 
Agnostus australiensis , Chapman, 1911, Proc. R. Soc. Viet., vol. XXIII. 
(N.S.), pt. II., p. 314, pi. LVIII., figs. 9, 11, 12. 
Description. —A specimen from Heathcote in the University collection 
shows the pygidium and traces of thoracic segments. The pygidium is oval, 
with a rather broad middle lobe, but narrowing towards the back. The 
specimen is crushed and slightly distorted, owing to its occurrence in a 
compressed, red shaly rock. In an oblique light the outline of the middle 
lobe can be distinctly made out, and its correspondence with Agnostus 
australiensis verified. 
Observations. —The occurrence of A. australiensis in the Heathcote fauna 
helps to support the view that the Dolodrook limestone area may be on 
practically the same horizon. The differences in the faunas from the two 
localities may be readily explained by the totally distinct lithological 
conditions of the beds in question ; that of Heathcote indicating a muddy 
shore-line, subject to deposits of detrital or terrigenous material, whilst the 
Mount Wellington area shows a deeper water and less turbid condition of the 
sea at that period. 
Fam. ?Olenid^). 
Genus Dinesus, R. Etheridge, jun. 
Dinesus ida, Etheridge fil. Plate VII., figs. 19-22. 
Dinesus ida (pars.), Etheridge, jun., 1896, Proc. R. Soc. Viet., vol. VIII. 
(N.S.), part I., p. 56, pi. I., figs. 1-4, 7. Gregory, 1902, ibid., vol. XV. (N.S.), 
pt. II., p. 154, pi. XXVI., figs. 8-10. 
Observations.— In Etheridge’s original description of Dinesus ida that author 
included the pygidium of another form, since named Notasaphus by Prof. 
Gregory. Thus the comparisons based on the Heathcote pygidia cannot 
hold good, but Mr. Etheridge makes some cogent remarks on the relationships 
of the cranidium of Dinesus, in which the affinity to Lloydia is pointed out, 
especially with regard to the feature of the circumscribed lobes at the base of 
the glabella ( loc . cit., pp. 59 and 62). 3 [In his original description, Etheridge 
states that the glabella of Dinesus has no furrows, and this is generally the 
case; but on one example, better preserved than usual, there are two 
transverse furrows anteriorly concave at the sides and meeting in a central 
1 Pal., New York, vol. I., 1847, p. 158, pi. XXXV., fig. 5. 
1 Mem. Serv. Geol. de l’lndocliine, vol. I., fasc. II., pt. II., 1912, pp. 36-37, pi. V., f. 10,11. 
* The genus Lloydia was suggested by Vogdes, who selected as genotype Batliyurus bituberculatus 
Billings (Geol. Surv., Canada, Palaeozoic Fossils, vol. I., 1865, p. 410, fig. 391). 
