Zygospiea putilia, Hall. 

 Page 362. 

 Figs. 31, 32. Dorsal and ventral views of a typical example. X 2. 

 Hudson River group . Pike county, Missouri. 



Glassia Romingert, Hall. 



Page 363. 



Fig. 33. A preparation showing the introverted coils and the direction of the 

 loop. X 3. 



Figs. 34-36. Ventral, profile and dorsal views of the exterior; showing the 

 smooth surface and bilobed anterior margins of the valves. X 2. 

 Trenton limestone. In a drift boulder near Ann Arbor, Michigan. 



Camarophobia rhomboid alis, Hall. 



Page 363. 



Fig. 37. Dorsal view of a rather small specimen. 



Figs. 38, 39, 40. Anterior, dorsal and ventral views of an.average adult possess- 

 ing a sharper median fold and stronger plication and showing the median 

 septum in each valve through the substance of the shell . X 2 . 

 Corniferous limestone, Peru, Indiana. 



LtoRHYNCHus Lesleyi, Hall. 

 Page 365. 



Figs. 41,42,43. Dorsal, profile and ventral views of a mature shell; showing 

 the rather obscurely defined median fold on the convex brachial valve, the 

 deep sinus, of the pedicle-valve and the unusually complete plication of the 

 lateral slopes. 

 Upper Devonian. Pennsylvania. 



392 



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