16 I'ROCHEDING.S OF THE MALACOLOGICAL ROCIF.TY. 



Tliis species differs from 31. lolata in tlie general tint of the internal 

 nacre and the composition of the valves and the periostracum. In 

 M. lohata the nacre is partly whitish and partly ,of an olive-greenish 

 tint, and the border of the valves is a deeper green. In the present 

 species the nacre exhibits an iridescent mixture of white, bluish, 

 gi-eenish, olive, and pinkish tints, whilst the margin is olive-brown. 

 The exterior, also, is of a rich deep brown or blackish-brown in the 

 present species, the periostracum being more fibrous. The structure 

 of the valves is much less solid, and consists of alternating calcareous 

 and chitinous layers. The solid valves of II. lohata are harder in 

 substance, and the periostracum is not so conspicuous. 



Two of the specimens of the present species have been attached 

 by their right valves and three by the left, and, as in the South 

 American species, these are more produced anteriorly than the 

 respective fi'ee valves. At the extremity of the umbo in better 

 preserved examples, the young shell would doubtless be visible. 

 I have much pleasure in naming the species after Mr. Daly. 



