466 
more or less preserved, and bears indistinct, obtuse, longitudinal ribs, crossed by very fine 
imbricating lamellse of growth. It is closely allied to Pinna laticosfata, Stoliczka,* * * § 
from tbe Arrialoor Group of India, and may possibly be so to Pinna australis, 
Iludleston.f 
Loc. Walsh Eiver A. G. Gregory). 
Pamily — MYTILID.®. 
Genus — IITTILUS (Linnesus), Lamarck, emend., 1799. 
(Prodrome — MsSm. Soo. Hist. Nat. Paris, 1799, p. 88.) 
Mxtiltts Tenisonwoopst, sy. non. 
My Ulus planus, Moore, Quart. Journ. Geol. Soc., 1870, xxvi., Pt. i., p. 252, 1. 13, f. 3. 
Sp, Char. Shell small, thin, ovate, compressed, nearly equilateral ; umbones 
terminal and acute, ventral margin rounded ; dorsal surface smooth, with depressed 
concentric lines of growth, crossed by very fine radiating lines, which wholly cover the 
exterior. Its flattened form, with its distinct ornamentation, readily distinguishes the 
species. {Moore.) 
Obs. The specific name applied by Mr. Moore to this shell had already been 
twice used before in the same sense. Eichwald employed it in the first instance for 
a supposed Palaeozoic My til us, but afterwards referred the shell to Avicula.X Kloden 
has likewise used the name planus for a Mesozoic 3Iytilus,% and under these circum- 
stances less confusion will be caused by changing it than by retaining it for the 
above shell. The name of the late Uev. J. E. Tonison Woods may appropriately 
be associated with it, as a very slight recognition of his labours in Queensland 
Palaeontology. 
As the interior of this shell is entirely covered with radiating lines, it may 
perhaps be referable to the genus Orenella, rather than to Mytilus proper. 
Loc. Wollumbilla {The late Rev. W. B. Clarke). 
MTTiiir.s EXTGOCOSTATPS, Moore. 
Mytilus rugocostatuSi Moore, Quart. Journ, Geol. Soc., 1870, xxvi., 252, t. 13, f. 2. 
Sp: Char. Shell thick, ovately oblong ; umbones terminal and acute ; posterior 
margin oblique and curved ; anterior side produced and somewhat rounded ; the dorsal 
surface is obtusely keeled, and towards the umbo has very coarse irregular concentric 
strim or lines of growth, which become finer towards the ventral margin. {Moore.) 
Obs. Unlike the Mytilidm generally, whose shells are usually thin and fragile, 
this species possesses a very thick test, especially in adult examples. When a 
portion of the test has adhered to the matrix, leaving an inner layer exposed on the 
shell, the striae are not seen, and the surface appears smooth, giving it the appearance 
of an entirely different species. {Moore.) 
Mr. G. Sweet has found at Bungeworgorai Creek, a Mytilus, two and a-half 
inches long, which is probably this species. 
I suspect that the 31ytilus, sp.,|| recently figured by Mr. Hudleston from the 
Lake Eyre Basin is but a well preserved cast of the present species. 
Loc. Wollumbilla {The late Rev. W. B. Clarke) ; Bungeworgorai Creek {0- 
Siveet — Colin. Sweet, Melbourne). 
* Pal Indica (Cret. Pauna), 1871, iii., p. 385, t. 25, f. 2 and 3. 
t Geol. Mag., 1890, vii. (3), p. 244, t. 9, f. 6. 
JLethsea Eossica, ii., p. 946. 
§ Verstein. Mark Brandenburg, 1834, p. 207, t. 3, f. 4. 
- II Geol. Mag., 1890, vii. (3), p. 245, t. 9, f. 9. 
