1849.] SHARPS ON THE SECONDARY ROCKS OF PORTUGAL. 177 



Artemis cordata, n. s. Pl. XXI. fig. 3 a & 3 b. 



Shell broadly ovate, very gibbose, with a depression on the ante- 

 rior margin near the beak : beaks large and incurved : shell covered 

 with small irregular concentric wrinkles. 



Length 1 inch ; breadth J, thickness | of an inch. 



In limestone of the subcretaceous series between Torres Vedras and 

 Sobral. 



The deep depression on the upper part of the anterior margin gives 

 this shell a cordate form when seen from the front. 



Plate XXI. fig. 3 a. Left valve. 



Fig. 3 b. Side view of the same specimen. 



Artemis elegantula, n. s. Pl. XIV. fig. 2 a & 2 b. 



Shell nearly circular, with prominent beaks ; gibbose ; covered with 

 regular concentric wrinkles between which are finer concentric lines. 



Length and breadth |ths of an inch. 



Abundant in the lowest beds of the hippurite limestone at Papel, 

 on the road from Lisbon to Cintra. 



A very elegant shell in form and marking ; the hinge has not been 

 seen, and the genus must be left in some doubt. 



Plate XIV. fig. 2 a. Exterior. 



Fig. 2 b. Cast of another specimen. 



Artemis inelegans, n. s. Pl. XX. fig. 3 a & 3 b. 



Shell broadly ovate, approaching a triangular outhne, slightly gib- 

 bose : beaks small and approximate : surface covered with irregular 

 concentric lines and wrinkles. 



Length 1^ inch; breadth 1 inch ; thickness fths of an inch. 



In limestone of the subcretaceous series in the cliffs at the Praia 

 de Ma9ams, north of the Cintra hills. 



Plate XX. fig. 3 a. Exterior. 



Fig. 3 b. Cast. 



Astarte? discus, n. s. Pl. XXI. fig. 4 a, 4 b, &; 5. 



Shell transverse, broadly obovate, irregular, nearly flat. Dorsal 

 margin straight : umbos very small and placed near the anterior ex- 

 tremity : anterior margin slightly excavated by a small, deep lunette : 

 ventral and posterior margins rounded : ligament concealed in a deep 

 hollow bounded by projecting sharp edges. Surface rough and un- 

 even with irregular concentric wrinkles, and originally ornamented 

 with dark irregular radiating lines. 



Posterior muscle placed away from the margin on a broad flat ele- 

 vation ; anterior muscle close to the margin and near the umbo ; third 

 muscle well-developed. # 



Length 2|- inches ; breadth 3^ ; thickness ^ an inch. 



From subcretaceous limestones between Sobral and Torres Vedras. 



I have not seen the hinge of this singular shell, and expect that it 

 will be found to constitute a new genus. The rough irregularity and 

 great flatness of the exterior, and the sharp edges which project above 



