G48 PROCEEDINGS OF THE XATIONAL MUSEUM. vol.52. 



upon the fifth, 18 upon the sixth, and 16 upon the penultimate turn. 

 These ribs extend prominently to the summit. Intercostal spaces 

 strongly impressed, about 2^ times as wide as the ribs. Suture mod- 

 erately constricted. Periphery of the last whorl feebly angulated. 

 Base short, ATell rounded, marked by the very feeble continuations of 

 the axial ribs, which become evanescent before reaching the umbilical 

 chink. Entire surface of the shell marked with fine, closely spaced, 

 spiral striations. Aperture oval, posterior angle obtuse; outer lip 

 thick ; inner lip thick, almost straight, and slightly revolute ; parietal 

 wall covered by a thin callus. 



The type. Cat. No. 250629, U.S.N.M., was collected by Mr. Gripp 

 on kelp, in 15 fathoms, outside of San Diego Bay. It measures — 

 length, 4.7 mm. ; diameter, 1.2 mm. 



TURBONILLA (PYRGISCULUS) GUILLENI, now species. 



Plate 44, fig. 5. 



Shell conic, milk white. Nuclear whorls 2|, well rounded, form- 

 ing a depressed helicoid spire, the axis of which is at right angles 

 to that of the succeeding turns, in the first of which it is about one- 

 third immersed. Postnuclear whorls somewhat inflated, well rounded, 

 almost appressed at the summit, marked on each whorl by 18 narrow, 

 well developed, rounded, almost vertical axial ribs. Some of these 

 ribs are developed into varices and these are distributed at irregular 

 intervals. Intercostal spaces about 2^ times as wide as the ribs, 

 crossed by three spiral series of strong pits, of which one is at the 

 periphery, the second a little anterior to the middle and the third 

 about two-fifths of the space between this and the summit posterior 

 to the median pit. In addition to these pits the intercostal spaces are 

 crossed by many almost equally strong incised spiral lines of which 

 12 occur between the summit and the first pit, 7 between the first and 

 median pit, and 8 between the median and peripheral pit. Suture 

 quite strongly constricted. Periphery of the last whorl well rounded. 

 Base moderately long, attenuated, marked by the feeble continuations 

 of the axial ribs and numerous incised spiral lines of a little wider 

 spacing than the fine sculpture on the spire. Aperture rissoid, oval ; 

 posterior angle obtuse; outer lip thick; inner lip short, curved, re- 

 flected over and appressed to the base; parietal wall covered with a 

 thick callus. 



The type. Cat. No. 267736, U.S.N.M., was dredged in shallow water 

 in Santa Maria Bay, Lower California. It has five postnuclear 

 whorls and measures — length, 3 mm. ; diameter, 1 mm. 



