NO. 2288. A^^TF MOLLUSKS OF THE FAMILY TURRITIDAE—DALL. 59 



suture and not continuous up the spire ; aperture narrow, anal sulcus 

 wide and round but with no marked fasciole or subsutural callus; 

 outer lip thick, infolded, the fine sculpture continued over the front 

 of the fold; inner lip erased, pillar straight, canal very short and 

 wide but distinct. Height of shell, 7; of last whorl, 4; diameter, 3 

 mm. Cat. No. 274101, U.S.N.M. 



Range. — Margarita Bay, Lower California; C. R. Orcutt. 



This shell has a curious resemblance in miniature to Alectrion 

 cooperi. 



Section NANNODIELLA DaU. 



Minute Turritidae with a glassy nucleus of several whorls finally 

 developing spiral threads, but otherwise smooth ; the adult sculpture 

 predominantly spiral, the anal sulcus large with a projecting mar- 

 gin, the outer lip in front of it thin and much incurved over the 

 aperture; the aperture unarmed, the canal short, the animal in- 

 operculate. 



Type. — Nannodiella nana., new species. 



This group is instituted for a number of minute species which are 

 remarkable for their relatively enormous anal sulcus, often half as 

 large as the aperture. Those so far recognized a.ve inhabitants of the 

 Gulf of California and its vicinity. 



PHILBERTIA (NANNODIELLA) NANA, new species. 



Plate 20, fig. 7. 



Shell minute, thin, whitish with touches of brown near the aper- 

 ture; nucleus translucent, the apex minute, globular, the whorls rap- 

 idly increasing, convex, smooth, except the fourth which develops 

 one or two spiral threads ; subsequent whorls four, with a prominent 

 sharp peripheral keel somewhat undulated but not swollen by axial 

 sculpture; the entire space between this keel and the preceding suture 

 is taken up by the arcuately striate nearly smooth, flattish anal 

 fasciole which is appressed at the suture; in front of the peripheral 

 keel is a less prominent keel on which the suture is laid, the space 

 between the two keels is divided into squarish shallow pits by axial 

 ridges; the base is spirally threaded with subequal interspaces, the 

 threads sometimes minutely scabrous from the intersection by axial 

 striation; aperture subtriangular, short, the anal sulcus not quite at 

 the suture, very large and deep the margin projecting; in front of it 

 the thin outer lip is produced and more or less incurved, the inner 

 lip with a wash of callus, the canal distinct, short, recurved. Height 

 of shell, 3.5; of last whorl, 2; diameter, 1.5 mm. Cat. No. 194857, 

 U.S.N.M. 



Range. — Off Cacachitas, Gulf of California in 26 fathoms. Also 

 off La Paz in 9 to 10 fathoms mud, and near Cape San Lucas. U. S. 

 Bureau of Fisheries. 



