PE Axeu 
a. Trapezoidal area, including central, middle j. Anterior lateral muscle scar. 
lateral, and outside lateral muscle scars. p. Pedicle groove. 
h. Central muscle sear. vs. Main vascular sinus. 
i. Transmedian muscle scar. ivs. Lateral branches of the vascular system. 
OBOLUS FEISTMANTELI (Barrande) (p. 391). 
[Pl]. XII, figs. 9 and 9a.] 
Ficure 1. Interior of ventral valve. Copied from Barrande [1879b, Pl. CVI, fig. 1v: 7A]. 
la. Cast of exterior surface of ventral valve, showing traces of concentric striz and lines of growth. Copied 
from Barrande [1879b, Pl. CVI, fig. 1v: 114A]. 
lb. Cast of interior of ventral valve. Original in the collection of the Museum of Comparative Zoology, Cam- 
bridge, Massachusetts; cast in the United States National Museum (Cat. No. 57088a). 
le. Cast of interior of ventral valve, showing lateral vascular canals. Original in the Museum of Com- 
parative Zoology; cast in the United States National Museum (Cat. No. 57088b). 
1d. Interior of the type specimen, a ventral valve. Copied from Barrande [1879b, Pl. CVI, fig. rv: 4A]. 
le. Cast of the interior of a dorsal valve, showing traces of lateral vascular canals. Original in the Museum of 
Comparative Zoology; cast in the United States National Museum (Cat. No. 57088c). (See fig. 9a.) 
li. Enlargement of a portion of a partly exfoliated shell, showing structure of shell. Copied from Barrande 
[1879b, Pl. CVI, fig. rv: 12f]. 
The specimens represented are all from Locality 303i, Lower Ordovician sandstone, Etage dl, Kruschna Hora, 
3ohemia. 
Oxso.Lus? ANCILLUS (Barrande) (p. 381). % 
Fieure 2. Partly exfoliated ventral valve, the type specimen, from Locality 303g, Lower Ordovician, Etage dl, 
Rabenberg, Bohemia. Copied from Barrande [1879b, Pl. CXI, fig. vi: 3A]. 
OBOLUS COMPLEXUS Barrande (p. 387). 
(Pl. XII, figs. 8 and 8a.] 
Fictre 3. Cast of interior of ventral valve, the type specimen, from Locality 303i, Lower Ordovician, Etage d1, 
Kruschna Hora, Bohemia. Copied from Barrande [1879b, Pl. CLII, fig. m: 4A]. 
3a. Interior of dorsal valve from Locality 303i, Lower Ordovician, Etage dl, Kruschna Hora, Bohemia. Copied 
from Barrande [1879b, Pl. CXIII, fig. v: A]. 
OBoLUs ? MIRANDUS (Barrande) (p. 405). 
Ficure 4. Ventral valve, the type specimen, from Locality 303k, Lower Ordovician, Etage dl, Hradischt, Bohemia. 
Copied from Barrande [1879b, Pl. CXI, fig. 1: 3A]. 
4a. Dorsal? valve from Locality 303k, Lower Ordovician, Etage dl, Hradischt, Bohemia. Copied from 
Barrande [1879b, Pl. CXI, fig. 1: 1A]. 
OBoLus? ADVENUs Barrande (p. 380). 
Ficure 5. Cast of interior of ventral valve, the type specimen, from Locality 303d, Lower Ordovician, Etage dl, 
Swarow, Bohemia. Copied from Barrande [1879b, Pl. XCV, fig. rv: 2A]. ; 
5a and 5b. Exterior and side view of dorsal? valve from Locality 303d, Lower Ordovician, Etage d1, Swarow, 
Bohemia. Copied from Barrande [1879b, Pl. XCV, figs. 1v: 1A and 2B, respectively]. 
OxsoLus? ROKITZANENSIS Barrande (p. 411). 
Ficure 6. Cast of the interior of a ventral valve, the type specimen, from Locality 303b, Lower Ordovician, Etage 
dl, in the environs of Rokitzan, Bohemia, showing strong radiating striae. Copied from Barrande 
[1879b, Pl. CXXVI, fig. 1: 5A). 
46 
