48 



be different states of A. ephippiwm. Suppressing all these, the genus is 

 now rich in species of fine size and brilliant colour from Australia, Cali- 

 fornia, Peru, and the Galapagos, Sandwich, and Philippine Islands.' 55 ' The 

 following have been recently described and figured in the ' Conchologia.' 



1. Achreus, Gray. 



2. Acontes, id. 



3. aculeata, Midi. 



4. adamas, Gray. 



5. aenigmatica, Ch. 



6. Alectus, Gray. 



7. amabaeus, id. 



8. argyritis, Reeve. 



9. caelata, id. 



10. costata, id. 



11. cytaeum, Gray. 



Species. 



12. Dryas, id. 



13. elyros, id. 



14. ephippium, Linn. 



15. fidenas, Gray. 



16. hamillus, id. 



17. Humphreysiana, R. 



18. lampe, Gray. 



19. laqueata, Reeve. 



20. larbas, Gray. 

 2L. lucerna, Reeve. 

 22. malleata, id. 



23. metallica, Reeve. 



24. nobilis, id. 



25. pacilus, Gray. 



26. placentella, Reeve. 



27. plenilunium, id. 



28. ramosa, id. 



29. scabra, id. 



30. sol, id. 



31. spinosa, id. 



32. strigilis, id. 



33. Tyria, id. 



Figure. 



Anomia adamas. PI. 26. Pig. 156. Shell, showing the perforated under 

 valve of a bright transparent reddish-orange species, found by Mr. 

 Cuming at Lord Hood's Island in the Pacific, affixed to a shell of the 

 large Avicula margaritifera. 



Genus 2. PLACUNANOMIA, Broderip. 



Animal ; similar to that of Anomia. 



Shell ; nearly equivalve, irregular, thin, sometimes rather solid, 

 generally smooth ; hinge internal, composed in the lower valve 

 oftioo converging teeth, in the upper oftivo ligamentary grooves ; 

 lower valve fissured, or triangularly perforated near the hinge, 

 perforation descending from the hinge, admitting a partially 

 bony muscle of adhesion which sometimes insinuates itself be- 

 tween the lamina of the shell. 

 In this genus, as in Anomia, a portion of the adductor muscle passes 



* The Anomia cenigmatica was found abundantly by Mr. Cuming at the Philippine Islands 

 attached to Mango-trees and Nipa Palms, growing between tides on the sea-shore. 



