j^o. 2288. NEW MOLLVSKS OF THE FAMILY TUBRITIDAE—DALL. 61 



This shell superficial!}'' resembles ^^Aesopus " oldroydi Arnold, 

 differing from the latter in details of sculpture, being more slender 

 and smaller, etc. It has more the sculpture of a Nannodiella than an 

 Aesopus and when adult probal)ly has the Nannodiella aperture. 



PHILBERTIA ( ? NANNODIELLA) AMYELA, r.ew species. 



Plate 20, lig. 8. 



Shell minute, thin, white, with a pervious axis and five whorls, 

 ■exclusive of the nucleus, of which one smooth whorl remains, the 

 apical part being defective; the sculpture begins abruptly and con- 

 sists of (on the spire two, on the last whorl three) fine very widely 

 spaced spiral threads, with four or five closer threads on the canal; 

 these cross (on the last whorl about 10) slender axial riblets (obsolete 

 on the base) also widely spaced, and at the intersections form min- 

 ute spinose tubercles ; the other axial sculpture consists of microscopic 

 crowded fine threads over the whole surface, more regidar and defined 

 than incremental lines ; the aperture is ovate, the anal sulcus obscure, 

 the outer lip (immature ?) thin, the pillar lip gyrate, the canal hardly 

 differentiated. Height of shell, 4.5 ; of last whorl, 2,5 ; diameter, 1.5 

 mm. Cat. No. 216944, U.S.N.M. 

 '" Range. — Panama, James Zetek. 



This shell recalls by its sculpture the Nannod/iella of the Gulf of 

 California, and if so related would have a different aperture at 

 maturity, 



PHILBERTLA HILAIRA, new species. 

 Plate 23, fig. 6. 



Shell small, translucent white, elevated, with two or more smooth 

 nuclear whorls (defective in the specimen) and five subsequent reticu- 

 lated, moderately rounded, slightly shouldered whorls; suture dis- 

 tinct, not appressed; spiral sculpture of (on the penultimate whorl 

 four) stronger threads the posterior forming the shoulder, and be- 

 tween them in the wider interspaces much finer intercalary threads; 

 on the base the minor threads become close-set and coarser; axial 

 sculpture of (on the last whorl fourteen or more) low threadlike ribs 

 extending to the canal and shortly sigmoid behind the shoulder; 

 aperture narrow, outer lip varicose, within smooth, though the spiral 

 sculpture shining through the translucent shell gives the effect of 

 liration; anal sulcus wide and shallow, canal hardlj'^ difl'erentiated. 

 Height of shell, 6.5; of last whorl, 4; diameter, 2.5 mm. Cat. No. 

 73925, U.S.N.M. 



Range. — Gulf of California, Stearns collection. 



This species has a higher spire than most of the genus, but can 

 hardly be separated from the others on that ground alone. It is pos- 

 sible that fresh specimens might show traces of color. 



