PLATE XCVII. 
Eoortuis primorpraLis (de Verneuil and Barrande) (p. 785). 
Fiaure 1. Ventral view of the type specimen, having the two valves united. 
la. Dorsal view of the specimen represented by figure 1. 
lb. The same, seen from the side. The area of the dorsal valve is a little too short. 
lc. The same, posterior view. 
1d. The same, seen from the front side. Most of our specimens are less thick. 
The specimen represented is from Locality 350, Middle Cambrian limestone near Adrados, Cantabrian Mountains, 
Province of Leon, Spain. The figures are copied from de Verneuil and Barrande [1860, Pl. VIII, figs. 6, 6a—d]. 
Nisusra (JAMESELLA) PELLICO (de Verneuil and Barrande) (p. 735). 
Ficure 2. Ventral view of the type specimen, showing area and deltidium. 
2a. Dorsal view of the specimen represented by figure 2. 
2b. Posterior view of same, showing areas of valves. 
The specimen represented is from Locality 350, Middle Cambrian limestone near Adrados, Cantabrian Mountains, 
Province of Leon, Spain. The figures are copied from de Verneuil and Barrande [1860, Pl. VII, figs. 7, 7a-b]. 
Nisusta? vatrcrna (de Verneuil and Barrande) (p. 730). 
Ficure 3. Dorsal view of the type specimen, with the two valves united, showing the area of the ventral valve. 
3a and 3b. Posterior and side views of same shell. 
The specimen represented is from Locality 350, Middle Cambrian limestone near Adrados, Cantabrian Mountains, 
Province of Leon, Spain. The figures are copied from de Verneuil and Barrande [1860, Pl. VIII, figs. 8, 8b—c]. 
EoortHIs BAVARICA (Barrande) (p. 775). 
Ficure 4. A distorted ventral valve, the type specimen, from Locality 303c, passage beds between the Upper Cam- 
brian and Ordovician, suburbs of Hof, Bavaria. Copied from Barrande [1868a, fig. 76]. 
EoortTHiIs LINNARSSONI (Kayser) (p. 782). 
Ficure 5. Dorsal valve from Locality C64, Upper Cambrian limestone 2.7 miles (4.4 km.) southwest of Yenchuang, 
Sintai district, Shantung, China. U.S. Nat. Mus. Cat. No. 52549a. 
5a. Ventral and dorsal valves from Locality 332a, Upper Cambrian at Taling, Liaotung, China. Type 
specimen copied from Kayser [1883, Pl. III, fig. 1]. 
EoortHis KAYSERI (Walcott) (p. 782). 
Ficure 6. Partly exfoliated, distorted ventral valve. U.S. Nat. Mus. Cat. No. 52546a. 
6a. Partly exfoliated dorsal valve, the type specimen. U.S. Nat. Mus. Cat. No. 52546b. 
6b. Cast of the interior of a dorsal valve. U.S. Nat. Mus. Cat. No. 52546c. 
The specimens represented are all from Locality ©64, Upper Cambrian limestone 2.7 miles (4.4 km.) southwest of 
Yenchuang, Sintai district, Shantung, China. 
BILLINGSELLA HICKsr (Salter MS.) (Davidson) (p. 756). 
Figures 7 and 7a. Ventral and dorsal views of the type specimen. 
7b. Cast of ventral valve. 
The specimens represented are from Localities 318d and 318p, Middle Cambrian sandstones in the Menevian at 
Porth-y-rhaw and Ninewells, near St. Davids, South Wales; Davidson does not say which. Figures 7, 7a—b are copied 
from Davidson [1869, Pl. XX XIII, figs. 14a, 13a, and 16a, respectively]. 
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