78 CONCHOLOGY. 



Malleus albus. Malleus vulsellatus. 



M. vulgaris. M. anatinus. 



M. normalis. M. decurtatus. 



M. vulgaris. The common Malleus. PI. 14, fig, 4. 

 Species with two earlike appendages ; trilobate, colour 

 blackish brown. 



M. albus. The white Malleus. 



Species trilobate ; base of the lateral lobe prolonged, with- 

 out a sinus ; the base and the pit of the ligament not distinct ; 

 colour white, with transverse undulations. 



M. vulsellatus. The tweezer Malleus. 

 Species slightly auricled. 



M. normalis. The square Malleus. 

 Species without earlike appendages. 



4. Avicula. Thirteen species. 



Remarkable for the form of its shell, which resembles, 

 when partially expanded, a bird flying. 



Shell foliaceous or not, thin and very fragile, always pearly, 

 sub-equivalve ; form sub-regular, but rather variable ; sum- 

 mit anterior; valves oblique, the left one with a little notch, 

 through which the byssus passes ; sometimes unequally and 

 obliquely auricled ; hinge linear, toothless, or with two small 

 rudimentary teeth ; ligament more or less exterior, placed in 

 a narrow groove, sometimes enlarged towards the summit; 

 one very large posterior muscular impression ; and one very 

 small anterior. 



Avicula macroptera. Avicula Tarentina. 



A. lotorium. A. Atlantica. 



A. semi-sagitta. A. squamulosa. 



A. heteroptera. A. papilionacea. 



A. falcata. A. cosiellata. 



A. crocea. A. physoides. 

 A. virens. 



