52 BULLETIN (iS, UNITED STATEW NATIONAL MUSEUM. 



TURBONILLA (STRIOTURBONILLA) HUMEROSA, new species. 

 Plate 3, i\g». 10. 10«. 



Shell elongate-c-onic, milk-white. Nuclear \\lioils very small, 

 two and one-half, tlepressed, helicoid, having their axis at right 

 angles to that of the succeetling turns, in the hrst of which they are 

 about one-fourth immersed. Post-nuclear whorls very strongly 

 rounded, moderately shouldered at the summit, marked by many 

 strong lamellar, protractivo axial ribs, which slope suddenh^' from a 

 point about one-third of the distance between the sutures, anterior 

 to the summit, giving the whorls a shouldered appearance at this 

 place. Of these ribs, 14 occur upon the second to fourth, 16 upon 

 the fifth to ninth, IS upon the tenth, and 20 upon the penultimate 

 turn. Intercostal spaces deeply impressed, double the width of the 

 ribs. Sutures strongly marked. Periphery of the last whorl well 

 rounded. Base short, well rounded. Entire surface of spire and 

 base marked by many fine, wavy, spiral striations. Aperture sub- 

 quadrate, posterior angle obtuse. Outer lip rather thick and some- 

 what revolute. 



The type (Cat. no. 206857, U.S.N.M.) was collected off Catalina 

 Island, California. It has twelv > post-nuclear whorls and measures: 

 Length 6 mm., diameter 1.7 mm. Two additional specimens (Cat. 

 no. 205937) were collected at San Diego, California. 



TURBONILLA (STRIOTURBONILLA) C-B-ADAMSI Carpenter. 

 Plate 3, tig. 3. 

 Chemnitziu C-B-Achniisi Carpenter, Cat. Maz. Shells. 1856. p. 427. 



Shell elongate-conic, milk-white. Nuclear w^horls two and one- 

 half, forming a moderately elevated helicoid spire, whose axis is at 

 right angles to that of the succeeding turns, in tlie first of whicli it is 

 about one-fourth immersed. Post-nuclear whorls slightly rounded, 

 slightly contracted at the suture, somewhat shouldered at the sum- 

 mit, marked b}' well-developed, rounded, somewhat protractive axial 

 ribs, of which 12 occur upon the first and second, 14 upon the third 

 to sixth, 16 upon the seventh, and 18 upon the penultimate whorl. 

 Intercostal spaces a little wider than the ribs, terminating at the 

 periphery, marked by very distinct, equally spaced, equal spiral stria- 

 tions. Sutures well marked, rendered wavy by the ribs. Periphery 

 and base of the last whorl well rounded. Aperture rhomboidal; 

 outer lip thin; columella moderately curved. 



The type and twelve specimens were collected ofi" Cha/na and 

 Spondylus at Mazatlan, Mexico. The type is on tablet 1990, Liver- 

 pool collection, British Museum. It has nine post-nuclear whorls, 

 and measures: Length 3.75 mm., diameter 0.9 mm. 



