66 THE NAUTILUS. 



interspaces are crossed by minute axial lamellae and the last 

 whorl has eight rather ill-defined wide axial ribs, most distinct 

 near the periphery. The shell is about 11 mm. long by 5.5 

 mm. wide, and 5 mm. of the length is included in the spire. 

 It may take the name of F. diminutus. 



F. porticus n. sp. This is a small purple-brown form which 

 may perhaps prove not to be a Fusimis, yet seems difficult to 

 refer elsewhere, so I adopt the term provisionally. It has three 

 conic, wine-colored, polished, nuclear whorls followed by a 

 little more than four sculptured whorls, having the general pro- 

 file of a slender Aledrion ; it has on the last whorl ten axial ribs 

 with wider interspaces ; the spiral sculpture consists of fine 

 rather sharp threads, two of which near the periphery are 

 slightly larger, and prominent where they cross the axial ribs, 

 with a single fine thread in the space between them ; on each 

 side of this pair between the sutures are three or four finer 

 threads ; the spire is longer than the aperture ; the outer lip 

 sharp, plain within, no callus on the inner lip, the canal short, 

 twisted and slightly recurved. Height of shell 11.0; of spire 

 7.0; maximum diameter 5.0 mm. It is an inhabitant of Pan- 

 ama. (U. S. N. M. No. 76275). 



F. centrifugus n. sp. Shell with three smooth conoid nuclear 

 whorls, followed by six and a half strongly sculptured whorls ; 

 suture appressed ; axial sculpture of numerous sharp thin ele- 

 vated lamellae, raised into a retractively looped frill in front of 

 the suture and similarly but less prominently looped between 

 its intersections with the spiral threads : on the last whorl are 

 eight prominent rounded ribs with subequal interspaces, which 

 extend from the suture to the base ; between the sutural frill 

 and the shoulder of the whorl are three inconspicuous spiral 

 threads ; on the shoulder one very prominent cord flattened and 

 produced at the summit of each axial rib into a spade-shaped, 

 not pointed, horizontal spine ; between this cord and another 

 less prominent cord in front, are one to three small spiral 

 threads ; a third still less prominent cord forms the margin of 

 the base in front of which are about a dozen spiral threads which 

 are more prominent on the canal. The color of the shell is 

 brownish, more livid inside the aperture ; the canal produced 



