518 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxin. 



der and an acute raised keel on the middle of the whorls between the 

 sutures, while a third ecjiialh' acute keel niarkyitthe periphery' of the 

 last whorl. Two other keels ornament the l)ase. the anterior one of 

 which is not quite as strong- as its neighbor. The axial sculpture con- 

 sists of narrow, more or less lamellar, almost vertical ribs, which 

 render the intersection with the spiral keels somewhat thickened but 

 not nodulose. These axial ribs extend over the periphery and base 

 of the last whorl to the umbilical region, gradually growing weaker 

 as they approach this point. There are about 18 on the second and 20 

 upon the penultimate whorl. The spaces between the ribs and keels 

 appear as concave quadrangular depressions. Umbilicus narrowly 

 perforated. Suture deeply channeled by the shouldered whorl. Aper- 

 ture suboval, posterior angle decidedly obtuse; outer lip thick, marked 

 by 5 projections, corresponding to the 5 keels; columella almost 

 straight, strongly revolute with a conspicuous oblique fold near its 

 insertion; parietal wall covered by a faint callus showing both basal 

 keels, the anterior faint and just posterior to the insertion of the col- 

 umella and the next on the middle of the wall. 



The type has 5 postnuclear whorls and measures: Length 2.7 mm., 

 diameter 1.3 mm. It and 3 additional specimens (Cat. No. 106502, 

 U.S.N.M.) were collected by Mr. Henry Hemphill at Scammons 

 Lagoon, Lower California. Three additional lots are in the U. S. 

 National Museum collection: Cat. No. 129336, 30 specimens collected 

 by Mrs. T. S. Oldroyd in the drift at San Pedro; Cat. No. 162843, 3 

 specimens also from San Pedro by the same donor; Cat. No. 62811, 

 1 specimen collected l\y Mr. Henry Hemphill at Ocean Beach, San 

 Diego, California. 



ODOSTOMIA (IVIDIA) NAVISA DELMONTENSIS, new subspecies. 

 Plate XL VI, %8. li. Set. 



Shell similar to O. (/.) natusa l)ut more elongate, and in every way 

 more delicate with the lamellose sculpture reduced almost to raised 

 cords and with stronger shouldered sunnnits and more open umbilicus. 



The type (Cat. No. 196297, U.S.N.M.) was collected by Mr. S. S. 

 Berry in 12 fathoms, ofi' Del Monte, Monterey Bay, California. It 

 has 5 postnuclear whorls and nieasures: Length 3,2 mm., diam- 

 eter 1.3 mm. 



Subgenus lOLAEA A. Adams. 



lolaea A. Adams, Proc. Zool. Soc, 1867, p. 310.— /o/c A. Adams, Ann. Mag. 

 Nat. Hist., 3d sen, V, 1860, p. 300, not Inic Blyth, .lourn. Asiat. Soc. 

 Beng., XIII, Pt. 1, 1844, p. 386. 



Shell umbillcated, marked by spiral cords, and axial riblets which 

 cross the grooves between them. 

 I'ype. — lole scitula A. Adams. 



