48 
K. L. Prexdergast. 
Pedicle valve with lamellar concentric ornamentation ; cardinal area 
elongate triangular with small triangular pseudo-deltidium. Internally Avith 
strong teeth, valve thickened postero-laterally with strong ridges bounding 
visceral portion laterally. Adductor muscles non-dendritic, narrow, on each 
side of median line; diductors longitudinally striate arising in front of 
adductors and extending from near middle line to lateral margin. Muscles 
set in distinct fossae. 
Brachial valve with ornamentation as in pedicle valve. Valve thickened 
anteriorly, regularly concave exteriorly but geniculate interiorly. Cardinal 
process trifid, strong, Avith sockets ax base; sockets separated by diagonal 
ridges from depressed muscular area. Posterior adductors elongate laterally, 
anterior adductors elongate antero-j^osteriorly. Brachial impressions arising 
from lateral edges of posterior adductors, following lateral and antero-lateral 
margins then turning backAvards toAvards median septum. Septum continuing 
about two-thirds length of valve. Cincture separating visceral disc from 
trail. 
Description of Holctifpe. — The holotype is an almost complete specimen 
Avith both A’alves in position. The pedicle A^alve is unfortunately weathered so 
that the external shell layers are absent. The valve is thick and of lamellar 
structure. The area is long and triangular, its Avidth equal to one-fifth of its 
length; it has a narroAAq closed, triangular delthyrium. The brachial valve 
is regularly concave and is ornamented by concentric lamellae, the edges of 
the lamellae forming the shell surface. It has a narroAv area disposed almost 
at right angles to that of the pedicle valAT. 
Description of Daratypes . — The paratypes are Iaa^o specimens, one a 
pedicle valve, the other a brachial valve, selected to shoAv the internal 
features of the species. 
In the pedicle valve (20400) the teeth are strong and du'erging from 
the hinge-line; laterally they are joined to a projecting ridge separating the 
ears from the visceral caA’ity. The shell is thickened in the region of the 
ears, the ridge continuing as a platform to the lateral margin, its continuity 
being broken up by a narroAv groove behind the ridge. This groove serves 
as a socket, a ridge on the brachial valve fitting into it. The muscle marks 
are distinct, the adductors elongate on each side of the middle line, arising 
almost under the teeth. The diductors are large, longitudinally striate, and 
anterior to the adductors they are separated by a rounded prominence in 
the middle line. 
Figure 8. 
Cardinal Process of Strophalosia kimberleyensis n. sp. (X3). 
