MALLEUS. 



so to two or three of them. There are no teeth in the 

 hfnge, and the umhones do not lie close together. The 

 ligament is for the most part external, lying between the 

 beaks, and attached in each valve to a triangular oblique 

 area or disk, with a central and, also oblique elongated 

 furrow, to which the principal portion of the ligament is 

 attached, though it is also spread over the two lateral 

 portions. 



The muscular impressions are two in each valve, one 

 of them is large, rather reniform and lateral, the other is 

 indeed very small, but it is also very distinct, and placed 

 near to and below the hinge on the side towards the sinus 

 for the passage of the byssus. This small muscular at- 

 tachment exists, also in several, if not all the other Genera 

 included by Lamarck in the Monomyaires : it was first 

 pointed out by Mr, I. D- C. Sowerby, in this Genus, as 

 well as in Ostrea. 



The Mallei are marine, and we believe all extra- 

 European; they are valued by Collectors, on account of 

 the singularity of their form and their rarity. In almost 

 all of them the imbricated foliaceous outside is extended 

 very far beyond the part which includes the animal, both 

 towards the apex and on the lateral lobes ; it is undulated 

 at its edges, and in the centre is a rather irregular blunt 

 longitudinal ridge. We are not aware of the existence of 

 any fossil species. 



Fig. I. Malleus vulgaris. 



' normalis, Lam, 



