10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 9I 



Apertui'e narrow and long, the outer lip deeply incised to form the 

 narrow sinus of the second keel and scalloped by the rest of the 

 keels and cords. Inner lip thin, reflected over and appressed to the 

 columella. The parietal wall is covered by a moderately thick callus. 



Type. — U.S.N.M. no. 429760, collected at station 26, on rough 

 bottom ofif the north coast of Puerto Rico, in 33 to 40 fathoms be- 

 tween latitude i8°3o'2o" N., longitude 66°22'o5" W. and latitude 

 i8°3o'3o" N., longitude 66°23'o5" W. It has 12 whorls and measures : 

 Length, 33.2 mm ; greater diameter, 9.0 mm. 



U.S.N.M. no. 430329 contains nine young specimens from the same 

 station. 



U.S.N.M. no. 429747 contains five young specimens dredged at 

 station 10 in 120 to 160 fathoms between latitude i8°29'2o" N., longi- 

 tude 66°05'30" W. and latitude i8°3o'24" N., longitude 66°04'i5" W. 



U.S.N.M. no. 430053 contains six specimens from station 104, on 

 rough bottom off the north coast of Puerto Rico, in 80 to 120 fathoms 

 between latitude i8°3o'4o" N., longitude 66°i3'2o" W. and latitude 

 i8°3o'io" N., longitude 66° 13' 50" W. 



POLYSTIRA MACRA, n. sp. 



Plate 3, figs. 8, 9, 13, 14 



Shell slender, fusiform, pale cream-colored with the columella white. 

 Nuclear whorls almost 2, the first 1.5 rather large, well rounded, 

 smooth, the last half marked by eight slender, not strongly expressed, 

 sinuous, rather distantly spaced, axial riblets. The postnuclear whorls 

 are marked by strong spiral keels, of which the second carrying the 

 sinus, is the strongest. The first is a little nearer to the summit than 

 to the second. The other two keels ornament the anterior half of the 

 whorls, the fourth one being at the periphery and the third midway 

 between this and the strong keel. The spaces between these keels vary 

 in width, that between the first and second being considerably nar- 

 rower than that between the second and third, which equals the space 

 between the third and fourth. All the spaces between the keels are 

 deeply concave. There is a slender crenulated thread at the summit 

 and another slender thread between the first and second spiral keel, 

 a little nearer the second than the first. A feeble spiral thread is 

 present about one fourth of the distance between the second and 

 third keel anterior to the second keel, and a second thread doubly 

 as strong as the last mentioned is a little nearer the third keel than 

 the second. Another spiral thread occupies the space midway between 

 the second and third. The axial .sculpture consists of rather strong. 



