PTERONOTUS. 87 



Described by A. Adams under the name of alabastrum which 

 is preoccupied by Reeve. Yery like M. triqueter, Born, but 

 differs in having only a single intervariceal rib. 



M. MACROPTERUS, Desh. PI. 40, fig. 517. 



Of the same general appearance and color as the three pre- 

 ceding species, and appearing like a particularly well-developed 

 M. lingua. The four-lobed, widely expanded, scabrous foliation 

 of the marginal varix is its chief characteristic. Length, 1'5 



inches. 



Hab. unknown. 



In the original figure the operculum approaches purpuroid, but 

 the nucleus is scarcely marginal. It has evidently been care- 

 lessly figured. Reeve's figure has the typical operculum of 

 Murex, 



M. TRIPTERUS, Born. PL 41, fig. 531. 



Columella and lip dentate, foliations very wide, oblique, regular. 

 Light yellowish-brown, darker within the aperture. 



Length, 2 inches. 



Red Sea, Ind. 0., Philippines (Upolu). 



M. PINNATLS, Wood. PL 41, figs. 526, 530. 



This well-known Chinese species attains a length of 2'5 to 3'5 

 inches. It is always pure white throughout. M. pellucidus, 

 Reeve (fig. 530), lt found upon a coral bottom at a depth of 7 

 fathoms, Island of Bantayan, Philippines,' 1 is evidently the same ; 

 in fact, I have before me a suite of specimens connecting the 

 two forms. 



M. CLAVUS, Kiener. PL 41, figs. 533, 534. 



Whitish or flesh-colored. Length, 3*25 inches. In the j'Oimg 

 shell (= M. bipinnatus, Reeve, fig. 534) the nodes and revolving- 

 striae are much more prominent. 



Philippines. 



#"-x- 



M. OSSEUS, Reeve. PL 41, figs. 525, 527. 



Whitish, more or less tinged with brown. Length, 2'75 inches. 



Hab. unknown. 



This is the first of a group of species in which the foliated 

 varices terminate on the shoulder of each whorl in a hooked 



