328 



regularly conical, whorls of slow increase, apex erect with the 

 tip immersed. Surface ornamented by crowded spiral striae, 

 broken up into narrow (-5 --75 mm.) transverse bands by slightly 

 curved incised lines. 



Last whorl globulose, large, a little higher than the length of 

 the spire. Aperture somewhat oblique, semilunate ; outer and 

 basal margins effusively dilated ; outer lip slightly ascending, 

 thin ; columella thinly ev^erted ; umbilicus simple, rather narrow^ 

 partly concealed by the everted columella border. 



Dimensions. — Length, 35 ; width, 24 ; height of aperture, 21 ; 

 width of aperture, 13 , width of umbilicus, 2 (vix). 



Locality. — Eocene : Glauconitic clayey sands, Adelaide-bore 

 (many examples). 



Remarks.— Thi^ interesting species is certainly congeneric with 

 Natica acuminata, Lamk., and X. Levesquei, D'Orb., transferred 

 by Cossmann to the section Euspira of the genus Amjndlina. It 

 agrees with them in the elevated and canaliculate spire, but is 

 readily distinguished by its regular spire (not subulate), effusively 

 dilated aperture, and elegant sculpture ; from A. acuniinnta, it is 

 further removed by being umbilicated, but reseml)les A. Levt^squei 

 in its simple umbilicus. 



Genus Sigaretus. 



Sig-aretus miepostira, -^pec. nor. Pi. vii., fig. 10. 



Shell depressed, narro\\' oblong-oval ; spire short, not at all 

 prominent ; suture concealed ; columella slightly thickened and 

 narrowly reflected, forming an open umbilical fissure. The 

 ornamentation consists of conspicuous undulations and coincident 

 strite, and of very slender and distant sjjiral threads and 

 coincident stria? ; the spiral ornament is hardly visible by the 

 unaided eye. and is confined to the median and posterior portions 

 of the body-whorl ; the sj^iral threads are closer together (the 

 interspaces only two or three times wider) and are more prom- 

 inent posteriorly, which are there conspicuously reticulated by 

 the transverse stride. 



Dimensions. — Length, 18 ; breadth, 13 ; height, 7, 



Locality. — EocEXE : Bird-rock Bluff (two examples). 



Affinities. — This new species has a resemblance in outline and 

 elevation of spire to >S'. Cuvierinnns, Recluz. The umbilical 

 fissure is open, not covered by a reflection of the columella, as is 

 usual among living congeners, in this particular S. microstira is 

 related to C. clathrafiis and some other species in the Eocene 

 of Europe, from all of which it differs Ijy its depressed and 

 elongate shape. 



Heligmope, t/eu. nor. 



Etymology — heligmos, a sinuosity ; ope, an aperture. 



