PTERONOTUS. 85 



M. Sowerby, in his latest monograph (Thes. Conch.), makes 

 the trigonulus of Reeve (not Lamarck) = pulcher, A. Ad., and 

 gives the Red Sea as locality. Adams, however, described his 

 pulcher as from St. Croix, W. Ind., 60 fathoms, M. Swenson ; 

 and I have made it a synonym of M. recurvirostris. Sowerby's 

 figure of pulchrr represents a trigonulus* 





 M. TRIQUETER, Born. PI. 40, figs. 506, 515. 



Length, 1*5 to 3 inches. 



Red Sea, Ind. 0., Philippines , Paumotus Is. (W. H. Pease). 

 M. rwrvh'nrfitx, So\vh. (tig. 515), is a synonym. 



M. RUBRIDENTATUS, Reeve. PL 40, fig. 50T. 



The foliated varices are not dentate as in M. triqueter, and the 

 lip has a row of teeth tipped with red. Length, 2'5 inches. 



'Hub. unknown. Two sp. in Cumingian Coll. 



M. BARCLAYI, Reeve, PI. 41, fig. 535. 



A much larger, wider species than M. triqueter, Born, with 

 which it is frequently confounded, and which is its nearest ally. 

 It is beautifully colored : pinkish, the ribs and varices golden 



yellow. Length, 3*5 inches. 



Mauritius. 

 M. TRIFORMIS, Reeve. PI. 40, fig. 511. , 



Uniform dull yellowish-brown. Shell thin, appearing as though 

 not adult. Length, 2 inches. On oyster-banks in 2-10 fms. 

 Probably fond of oysters. 



Port Lincoln, Austr. (Angas). 



M. BIPUNCTATUS, Sowb. PL 40, fig. 509. 



Orange colored, the varices striped with red ; two intervariceal 

 purple spots on the shoulder. Length, T25 inches. 



Austr. 



Very close to M. trifbrmis^ Reeve ; the purple spots are the 

 only important distinctive character. 



M. ACANTHOPTERUS, Lam. PL 40, fig. 512. 



Whitish, stained more or less with light brown. Somewhat 

 related to the preceding species. Length, 2 '25 inches. 



Watson's Bay, N. 8. Wales (Angas). 



