PHYLLONOTUS. 107 



M. SPINICOSTATA, Yal. PI. 23, fig. 207 ; pi. 28, fig. 251. 



Very closely allied to the three preceding species, and may 

 prove to be identical with them. It is more spinous and less 

 frondose, larger in size and different in color, being white with 

 pink brown on the principal narrow ribs ; it comes moreover from 

 the West Indies. A. single, much battered dead specimen found 

 at Beaufort, North Carolina. Length, 5 inches. 



M. HIDALGOI, Crosse. PI. 27, fig. 246 a. 



Somewhat thin ; uniform light brown ; varices six, frondose, 

 long spiny on the shoulder ; lip varix broad, fimbriate spinose. 

 Length, 1*4 inches. 



Dredged from coral heds in West Indies, at great depth. 



Its nearest ally is M. spinicostata, Vol. ; from which it is dis- 

 tinguished by its smaller size, shouldered whorls and more 

 foliated varices. 



M. QUADRIFRONS, Lam. PI. 17, fig. 170 ; pi. 19, figs. 176-178 ; pi. 

 28, figs. 254-256. 



Yarices four, the inter-space with one not very prominent 

 tubercular rib and sometimes a trace of a second. Yellowish or 



brownish. Length, 2'5 to 4 inches. 



West Africa. 



This was at first supposed to be an accidentally four variced 

 variation of M. brevifrons. Lam., but the occurrence of specimens 

 in the Taylor collection recently studied by Mr. Sowerby, the 

 agreement with a miocene four variced fossil species named by 

 Mr. Toumouer M. Bourgeoisii, (fig. 256), and a fine example in 

 our collection in Philadelphia, make it expedient to treat it as 

 distinct. M. megacerus, Sowb., (figs. 177, 178), ( = M. Moquini- 

 anuSj Duval, fig. 170), appears to be a variety of lighter growth. 

 Mr. Sowerby (Thes. Conch.) admits the identity of his M. cas- 

 taneus, (fig. 176), with M. quadrifrons. 



M. VARJUS, Sowb. PL 27, fig. 246 ; pi. 28, fig. 253. 



Subrhomboidal, with revolving, alternately larger, bead-like 

 striae ; varices four to six, spinous at the shoulder and occasion- 



