13. rugosa, Lam. 



14. spoiigiarum, id. 



65 



15. Tasmanica, Lam. 16. trita. 



Figure. 



Vulsella attenuata. PL 28. Fig. 166. Shell, showing its elongated 

 tongue-like growth. 



Genus 3. MALLEUS, Lamarck. 



Animal ; undescribed. 



Shell ; irregular, nearly equivalve, elongated, sometimes lobed on 

 each side ; umboes divaricate ; hinge toothless, with the liga- 

 ment partly external, on a sloping area, partly internal within 

 a central pit, ivilh a small passage for the byssus. 



The genus Malleus was founded for the reception of two oyster-like 

 shells of very remarkable longitudinal growth, of which the hinge portion 

 is prolonged on either side, at a right angle, into an extended narrow lobe. 

 The term malleus, a mallet or hammer, aptly designates this form. But 

 in none of the species since discovered, with the same natural affinities, is 

 the hinge portion lobed. The Hammer Oysters have as many as eleven 

 species associated with them in this genus in which there is no hammer 

 structure, and in at least half of them, which are very small, the laminated 

 growth soon terminates, forming a kind of nucleus, and the remaining por- 

 tion of the shell is an independent transparent deposit of brittle calcareous 

 matter, characterized in most instances apart from the body of the shell by 

 a different speciality of colouring. 



The large Mallei are from the islands of the Eastern Seas, the small 

 brittle species are from West Columbia and the islands of the Pacific. 



1. albus, Lam. 



2. anatinus, id. 



3. aquatiiis, Reeve. 



4. dsemoniacus, id. 



5. decurtatus, Lam. 



Species. 



6. legumen, Reeve. 



7. maculosus, id. 



8. rea-ula, Forsk. 



10. solitarius, Reeve. 



11. tigrinus, id. 



12. vesiculatus, id. 



9. rufipunctatus, Reeve. 13. vulgaris, Lam. 



Malleus anatinus. 

 vol. II. 



Figure. 

 PL 28. Fig. 167. Shell, showing the hinge h'ga- 



