PLATE 48. 



Page 



Fig. 1 a- y- Pentamerus verneuili ( n. s.). 260 



1 a,b. Ventral and front views of a young specimen. 

 1 e, d. Dorsal and profile views of a specimen larger than the preceding. 

 1 e. The cardinal view of 1 c, d enlarged, showing the triangular foramen and apparent area. 

 1 /. Dorsal valve of a finely plicated specimen. 



1 h. The same enlarged, to show the regularly intercalated smaller plications. 

 1 g. Ventral view, showing the bifurcating plications. 



1 t, fc, I. Ventral, dorsal and profile views of a specimen with simple coarse plications. 

 1 m. Front view of a specimen similar to the preceding. 



1 n, 0, p. Ventral, profile and front views of a large specimen which preserves the prevailing 

 character of the species. The profile view shows the incurved dorsal beak, and the nearly 

 straight ventral beak, a little separated. 



1 r. Cardinal view, showing the short accessary plications which mark the lateral areas. 



1 s. Profile view of another specimen, showing the beaks of the two valves in contact, the 

 usual condition of the shell. 



1 t. Interior of the dorsal valve, showing the two longitudinal septa and the broad brachial 

 processes at the hinge line. 



1 u. Interior of the ventral valve, showing the elongate spoonshaped cavity, with the lateral 

 lobes and the slight extension of the central septum. 



1 X. The same enlarged, showing the muscular imprints at the base of the cavity. 



1 V. Interior of the two valves in connexion, showing the triangular cavity and central septum 

 below and the double septa above with the lamellaj, which extend far into the interior of 

 the upper or dorsal valve. 



1 y. Longitudinal section of the dorsal valve, showing the comparative extent of the spoon- 

 shaped cavity and the narrow short septum below. 



Fig. 2 a- I. Pentamerus pseudogaleatus ( n. s.). 259 



2 o, b, c, d. Dorsal, profile and front views of young individuals. 



2 e. Dorsal view of a specimen of medium size. 



2/, g. Front and profile views of the same specimen. 



2 A, i. Profile and front views of a very gibbous specimen, which represents the character of 

 the ordinary full-grown individual. 



2 k, I. Dorsal and profile views of an unusually large specimen from which the shell is par- 

 tially exfoliated, showing the two septa of the dorsal valve. 



