ART. 22 SAN PEDRO FAUNA OLDROYD. 27 



Type.—C2it No. 333509, U.S.N.M., has lost the nucleus and the 

 first nuclear turn. The nine remaining measure: Length, 7.9 mm.; 

 diameter, 2.3 mm. 



The nuclear turns were described from a young specimen, Cat. 

 No. 352508, U.S.N.M. ; 38 additional specimens are entered as Cat. 

 No. 352533, U.S.N.M.; 150 are in the Oldroyd collection. 



This specimen is related to Turhonilla (Pyrgolwmpros) taylori^ 

 Dall and Bartsch, but is much smaller than that species, and has more 

 ribs. The fine spiral striations have been omitted in the figure. 



TURBONILLA (PYRGISCUS) HIMERTA. new specieg. 



Plate 1, fig. 1. 



Shell moderately large, pale yellow. Nuclear whorls two and a 

 half, well rounded, forming a decidedl}^ repressed helicoid spiral, 

 the axis of which is almost at right angles to that of the succeeding 

 turns, in the first of which the tilted edge of the nuclear spiral is 

 about one-fourth immersed. Postnuclear whorls narrowly shoul- 

 dered at the summit, almost flattened in the middle, marked by 

 20 weak, slightly retractively curved, axial ribs on the first turn. 

 On the second turn and the succeeding turns there are strong axial 

 ribs, which have a protractive slant. Of these ribs, 18 occur upon 

 the second to fifth, 20 upon the sixth, 24 upon the seventh, where 

 they begin to have a slight retractive curve, while on the last turn 

 there are 38, which have a decided retractive curve. The spaces 

 separating these ribs are narrow on the first turn, about as wide 

 as the ribs on the succeeding two, and a little wider than the ribs 

 on the next two, while on the last they are a little narrower than 

 the ribs. The spiral sculpture consists of a series of incised lines 

 and pits. The widest pits are the line at the periphery, where the 

 diameter equals the height. Another series of pits is about half 

 the width of the peripheral, and occupies a space halfway between 

 the summit and the periphery, while a third series of about equal 

 width occupies the space a little nearer to the peripheral than the 

 median line of pits. The two series of pits posterior to the median 

 pits follow next in strength and are equal. In addition to this, 

 there are incised spiral lines, of which the first is about half as far 

 removed from the summit as it is from its neighbor anteriorly, the 

 space between the first and second being equal to about one-sixth 

 of the width between the summit and the periphery. The second, 

 third, and fourth incised lines are equal and rather closely spaced. 

 These are followed by the two medium-sized pits already referred 

 to, posterior to the median pits, then by the median pits. The space 

 between the median pit and the medium-sized pit anterior to it 

 is crossed by two incised spiral lines, of which the first is a little 



