PLATE 4 



Pterinea fasciculata Goldfuss van occidentalis Clarke 



Page 27 



i, 2 Left valves of usual size 



3-5 Right valves showing the differences in sculpture in the two 



valves. Figures 4, 5, x 2 

 6, 7 Left valves, x 2, expressing the fasciculate ribbing 



Pteronitella hirundo Clarke 



Page 29 



8 A left valve 



9 A right valve showing the characteristic form and strong radial hinge 



striae 



10 A typical left valve 



1 1 Conjoined valves, exposing an internal cast of the right and a sharp 



sculpture impression of the left 



Pteronitella passer Clarke 



Page .,0 



12-14 Three left valves showing the subrhomboidal outline 



Macrodus matthewi Clarke 



Page 34 



15, 1 6, 1 8 Three right valves; 15, x i^ ; 16, 18, x 2 



1 7 A left valve, x 2 



Macrodus ? baileyi Clarke 



Page 34 



19, 20 Right and left valves, natural size 



Goniophora ? sp. 



21 A right valve 



Goniophora curvata Clarke 



Page 31 



22, 23 Two right valves 



Sphenotus ellsi Clarke 



Page 32 



24 A small right valve 



25, 26 Specimens showing conjoined valves 



174 



