PLATE 7 

 Palaeoneilo (Nuculitesj folles Clarke 



Page 36 



1-3 Left and right valves and internal cast, natural size 

 Nuculana (Ditichiaj securis Clarke 



Page 37 



4-9 Lediform shells showing in most the impression of the clavicle on the 

 posterior slope, in figure 6 on the anterior slope 



Rensselaeria stewarti Clarke 



Page 38 



10-12 Three views of the exterior, x i]/£ 

 13, 14 Dorsal and profile views of a smaller shell 

 15, 16 Exteriors of ventral valves 



1 7, 1 8 Internal cast of ventral valve showing the cardinal flattening or 

 pseudoarea and the character of the muscle scars 



19 Internal dorsal cast, showing cardinal area and muscle scars 



20 Enlargement of the dorsal cardinal cast showing the area and the filling 



of the perforation of the cardinal plate 



Trematospira perforata Hall van atlantica Clarke 



Page 41 



21, 22 Opposite sides of the same shell 

 23 Cardinal view of conjoined valves 



Sieberella pseudogaleata Hall 



Page 39 



24, 26 Views of a ventral valve 

 25 The dorsal valve showing septa 



Cyrtina chalazia Clarke 



Page 40 



27-32 Three views each of two shells (27-29, 30-32). x 1^ 



180 



