PLATE I. v6 
SCHIZOPHOLIS RUGOSA Waagen (p. 609). 
[Pl. LXXXT, figs. 1, la-c.] 
Fieure 4c. Interior of a dorsal valve from a cast made in a natural mold. The casts were obtained first by dissolving 
the shells and then taking wax and plaster casts of the uninjured natural molds. From Locality 
357c, the Neobolus beds of the Khussak group of the Middle Cambrian, Kiura, Salt, Range, India. 
Original in the collection of the Geological Survey of India (Cat. No. 3/780); cast in the United States 
National Museum (Cat. No. 56910a). 
VOLBORTHIA RECURVA (Kutorga) (p. 366). 
[Text figs. 33A-B, p. 366.] 
Freures 6, 6a, 6b, 6c, and 6d. Posterior, side, front, ventral, and dorsal views of the type specimen, a partly 
exfoliated shell which has the two valves united, from Locality 336g, Ordovician glauconitic lime- 
stone at Zarskoe Selo, Government of St. Petersburg, Russia. 
6e. View of the false area of the ventral valve represented in figs. 6, 6a-d. The false area of this shell has 
been illustrated by photography in text figs. 33A and 33B, p. 366. 
Figures 6, 6a-e are copied from von Moller [1874, Pl. VII, figs. 1-6, respectively]. Original specimen in the col- 
lection of the Museum at Reval, Esthonia, Russia; cast in the United States National Museum (Cat. No. 58298). 
