MESODESMA. 
Deauratum, 53. 
Donacilla, 53. 
M. ? Castaneum, 54, 
AMPHIDESM A. 
Prismatieum, 54. 
Tenue, 55, f. 24. 
Boysii, 55. 
CORBULA. 
Nucleus, 56. 
SPHAENTA. 
Binghami, 57, f. 32, 33. 
Swainsoni, 57 (0). 
Costulata, 245. 
PANDORA. 
Obtusa, 57, f. 15. 
Rostrata, 58. 
HIATELLA. 
Rugosa, 58. 
Arctica, 59. 
aeas 
xXvi 
AGINA (p). 
- Purpurea, 60. 
LI” 
VENERUPIS. 
Irus, 60. 
Perforans, 61. 
PETRICOLA. 
Ochroleuca (Psammobia 
Fragilis, 62). 
PSAMMOBIA. 
Tellinella, 62. 
Costulata, 62. 
Laskeyi, 63. 
Polygoua, 63. 
Ferroensis, 64. 
SANGUINOLARIAZ, 
Rugosa, 64. 
Vespertina, 68. 
TELLINA. 
LTineata, 65. 
Punicea, 66. 
OS rw 
(0) Not impossibly the young Mya Arenaria. 
(p) Scarcely differing from H1aTELLA. 
