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NO. 2193. WE82' AMERICAN 3IARIXE M0LLU8K8—BARTSCH. 653 



TURBONILLA (PYRGISCUS) BARTOLOMENSIS, new species. 



Phite 45, fig. 5. 



Shell conic, yellow. Nuclear whorls decollated. Postnuclear whorls 

 appressed at the summit, flattened in the middle, except the last, 

 which is inflated and strongly rounded. The whorls are marked by 

 rather strong, well-rounded axial ribs, which are slightly retrac- 

 tively slanting on the early turns and decidedly so on the later 

 volutions. Intercostal spaces about as wide as the ribs marked by 

 12 deeply incised spiral pits. Of these the fifth is a mere line, while 

 the first four, the sixth, ninth, and tenth are about twice as wide, 

 and the eighth and ninth and eleventh and twelfth form deep broad 

 pits fully three times the width of the last. Suture moderately con- 

 stricted. Periphery of the last whorl strongly inflated, well rounded. 

 Base short, inflated, well rounded, marked by the continuations of 

 the axial ribs, which extend strongly to the umbilical area, between 

 which poorly defined spiral striations may be seen. Aperture short, 

 broadly oval, posterior angle obtuse; outer lip thin, showing the 

 external sculpture within ; inner lip short, partly reflected, free, pro- 

 vided with an obsolete oblique internal fold at its insertion ; parietal 

 wall covered by a very thick callus, which renders the peristome 

 complete. 



The type. Cat. No. 268729, U.S.N.M., was dredged in shallow 

 water in San Bartolome Bay, Lower California. It has lost the 

 nucleus, the nine postnuclear whorls measure — length, 5.6 mm.; 

 diameter, 1.6 mm. 



This special resembles Tii^^honilla (Pyrgiscus) duricoifna Dall and 

 Bartsch in having the inflated last whorl and the reddish incised 

 spiral lines, but differs markedl}^ from it in shape and sculpture. 



TURBONILLA (PYRGISCUS) LAMNA. new Bpedes. 



Plate 43, fig. 1. 



Shell regularly, broadly elongate conic, j'^ellowish white. Nuclear 

 whorls 2^ smooth, forming a decidedly depressed helicoid spire, the 

 axis of which is at right angles to that of the succeeding turns in 

 the first of which about one-fourth of the side of the spire is im- 

 mersed. Postnuclear whorls well rounded, appressed at the summit, 

 ornamented by weak, distantly spaced, somewhat protractive axial 

 ribs, which become flattened and decidedly enfeebled near the sum- 

 mit. Of these ribs 20 occur upon the first and 18 upon the re- 

 maining turns. Intercostal spaces about three times as wide as 

 the ribs, shallow, crossed by 13 slender incised spiral lines of some- 

 what varying width. Of these lines the first to fifth, seventh and 

 twelfth are mere incised lines, while the sixth, eighth, tenth, and 



