ETCHEMINIAN FAUNA OF CAPE BRETON. 207 



smoother surface and narrow fold at the cardinal line. No Silurian 

 Schmidtella has the pointed valve of this species. 



DESCRIPTION OF THE PLATES. 

 Plate I. 



Fig 1. Lingulella Gregwa, n. sp. — a Ventral valve ; b interior of 

 same ; — c Section of same ; — d Dorsal valve ; — e mould 

 of interior of same ; f Section of same. All mag. \. 

 Seep. 199. 



Fig. 2. Lingulella tumida, n. sp. a Ventral valve ; h mould of 

 interior of same ; — c Longitudinal section of same. All 

 mag. \. See p. 200. 



Fig. 3. Leptabolus (?) collicia, n. sp. a Ventral valve ; b Dorsal 

 valve; — c Interior of a broken ventral valve. All mag. ^ ; 

 — d Another venti'al, showing the callus of the visceral 

 cavity, mag. |; — e Section of the two valves, mag. a. 

 See page 200. 



Plate II. 



Fig. 1. Leptobolus afavus, n. sp. — a Ventral valve ; — b Mould 

 of the interior ; — c Longitudinal section of same ; — d 

 Dorsal valve ; — e Mould of the interior. All mag. ^. 

 — /'Portion of the outer surface of the shell. Mag. 4 T °. 

 See p. 200. 



Fig. 2. Obolus ( Palceobolus ) Bretonensis, n. subgen. et sp. ; — a Ven- 

 tral valve ; — b Interior of same ; — c Longitudinal sec- 

 tion ; — d Dorsal valve; e Interior of same; — f Longi- 

 tudinal section. All mag. \ ; — g Portion of outer sur- 

 face of the shell, mag. \ ; — h smaller portion, mag U> ; 

 — i Section of the two valves, mag f . See p. 202. 



Plate III. 



Fig. 1. Acrothele avia, n. sp. a Portion of a ventral valve; b Longi- 

 tudinal section of same. Both mag. j- ; — c Interior of a 

 ventral valve ; — d Dorsal valve; — e Longitudinal sec- 

 tion of same ; —f Interior of a dorsal valve. The four 

 mag. \ — g Enlargement of the outer surface of the 



