;50 
K. L. Prendergast. 
tively the radial markings may be the result of weathering. No pits^ such 
as would indicate the presence of spines, have been observed and it would 
seem, therefore, that this species is non-spinous. 
The variation within the species is also reflected in the internal structure 
of the brachial valve. The median septum may be equal in length to half 
or increase up to two-thirds of the length of the visceral disc. The brachial 
impressions may follow closely the lateral margin or be placed some distance 
from it. 
Bemar'ks . — The most peculiar characteristic of this species is the nature 
of the visceral cavity, the thickened region of the ears and the ridge projecting 
into the cavity. This may be seen externally, when the brachial valve becomes 
squashed in, showing the shape of the cavity. 
Comparison n'ith other species. — I regret that I have been unable to 
trace the type of S. clarkei (Eth.), which belonged to the Daintree Collection. 
Externally this species resembles S. clarkei^ though it differs in many respects, 
as Etheridge (1903, p. 21) has already pointed out. With more and better 
specimens many of these distinctions cannot now be maintained, but this 
species, S. kimherleifensis is distinct in the depressed umbonal region, rela- 
tively longer hinge-line and concave rather than flat brachial valve. Internally, 
it occupies a ])osition intermediate between S. clarkei and S. jukesi. In 
S. clarkei the median septum is as long as the visceral disc and the bracliial 
impressions are transversely elongated; in S. jukesi the septum is short and 
the brachial iinjiressions narrow. Thus in S. kimherlei/ensis with short median 
septum and wide brachial impressions we see a species with characters of 
both the other species. Externally the species is distinct from S. jukesi and 
-8. gerardi in the absence of spines. 
Strophalosia multispinifera n. sp. 
PI. vi, figs. 6-8, 
Holofype. — U.W.A. 204.58. Scarp two miles east of Cliristmas Creek Home- 
stead, Kimberley Pivision. Nooneanhah Series. 
Topoiypes. — P.W.A, B 74. Same locality and horizon. 
Other Material. — I^.W.A. 20456, Hill 0., south of road, Grant Pange, Kim- 
berley Division. Nooneanhah Series. 
Biagnosis . — Pedicle valve large, swollen, transversely oval in outline, 
hinge-line less than greatest width of shell. 
Ornamentation of fine oblique spines with regular quincuncial arrange- 
ment; group of spines on each ear. Valve Avith elongate area, triangular 
delthyrium. Cicatrix small. Teeth large. Brachial valve unknown. 
Description. — The pedicle Amlve is evenly convex Avith a slight median 
depression, not sufliciemly marked to be termed a sinus. It is 45 mm. high, 
Avith maximum Avidth of 49.6 mm., AA'hile the hinge-line is 34.8 mm. long. 
The surface of the vah’e is marked by closely spaced sjnne bases arranged 
in irreg’ular quincunx; it is ]Arobable that these ga\’e rise to small forward 
projecting spines, but no si>ines are preserved on the body of the shell. 
The spines have a density of 6 in 10 mm. measured transversely at a distance 
of 20 mm. from the umbo. The spines become more closely packed on the 
ears to give a compact group at each end of the hinge-line. They are closer 
together and more h’regular anteriorly. The area is short, its Avidth approxi- 
mately half its length; it is longitudinally striated and interrupted by a 
