138 M1TRULARTA. 



M. Roissyi, Dufo, Lithedaplius longirostria, Owen, M. dormitoria, 

 Reeve (fig. 60), M. ossea, Reeve (fig. 39), H. Hipponiciformis, 

 Reeve (figs. 40, 41), M. cyathella, Reeve (fig. 42), M. bulla, 

 Reeve (tig. 43), M. slultorum, Reeve (fig. 44), M. Tongana, Quoy 

 (figs. 45, 46), M. pileopsis, Quoy (figs. 47, 48), M. chlorina, 

 Gould (figs. 49-51), M. radiosa, Gould (fig. 52). These forms 

 represent a great variety in shape and sculpture, and it is not 

 wonderful that, with the ideas prevalent among conchologists a 

 quarter of a century ago, they were described as distinct 

 species. I have, for convenience, separated a series of irregu- 

 larly corrugated forms as a variety, but they really connect 

 insensibly with the type. 



Tar. TORTILIS, Reeve. Figs. 53-59, G1-6T. 



Surface irregularly corrugated and folded, the folds longi- 

 tudinal, oblique or concentric, sometimes taking every direction, 

 and so thick as to obscure the radiating stria 1 . 



West Indies , Philippines. 



This form is very usual, especially in West Indian specimens. 

 M. diaphana (fig. 54), Reeve, M. Martiniana, Reeve (fig. 55), 

 M. uncinata, Reeve (fig. 5'7), M.papyracea, A. Ad. (figs. 58, 59), 

 M. cornea, Reeve (figs. 61, 62), M. cicatricosa, Reeve (fig. 56), 

 M. saccharimeta, Reeve ffig. 63), M. Balanoides, Reeve (fig. 64), 

 M. porosa. Reeve (figs. 65, 66), and M. fibulata, Reeve (fig. 67), 

 are all synonyms. 



Tar. ACULEATA, Reeve. Fig. 70. 



Radiately striate and scaled, or short spinose. 



Honduras. 



M. tubifera, Gray (un figured), from the same locality, is doubt- 

 less a synonym. 



M. CORRUGATA, Brod. PI. 43, figs. 68, 69. 



Suborbicular, apex subcentral, rugosely radiately ribbed and 

 striated, ribs scaly towards the margin ; whitish, or light }-ellow- 

 ish brown. Diam. 40 mill. 



Guacomayo, Central America. 



Found by Cuming, under stones at 14 fms. A beautiful form, 

 but perhaps not specifically distinct from M. equestris. 



