N(..Uo2. NOTES ON PYRAMIDELLID.F.—DALL AND BARTSCH. 341 



Atliuitic .side, especially iiboiit Vera Cruz. It i.s, therefore. (|uite 

 likely that this may be the home of the present species. 



O.ryfrema was proposed by Ratinesciue for a genus of Mel((nian.<<. 



NISITURRIS, new subgenus. 

 Plate XXIV, fig. 3. 



This subgenus is proposed for TurlxmHIa {X.) cnjstdlUna, which is 

 differentiated from all the Turbonillas which w^e have seen by its ver}'^ 

 peculiar nucleus. The nucleus in TurltoniUa is helicoid or planorboid; 

 in this individual, hoAvever, it is pupoid — that is, the nuclear whorls 

 resemble a small sinistral pupa placed obliquely on the later whorls. 

 The post-nuclear charactei's are those of Chemnltzia s. s. 



TURBONILLA (NISITURRIS) CRYSTALLINA, new species. 



Plate XVII, fig. 7. Plate XXIV, fig. 3. 



C'hemnUzia crystalUna Dunker, Cat. Mus. Godeffroy, IV, 1869, p. 78 (a nomen 

 nudum), not Pyramis crystalUna Brown, 1827 { = Odostomia) nor Odostomia 

 cry.4allina Garrett, 1873 { = Pyramidella (Iphiana) crysiaUina), nor Odos- 

 tomia (AuricuUna) crystalUna Monterosato, see Carus. Prod. Fauna Medit., p. 

 275, 1893; =0. d iaphana Jeflreys. 



Shell very slender and thin, elong-ate-conic, slig-htly umbilicated, 

 almost transparent. Nuclear whorls large, very much elevated, coiled 

 to resemble a small sinistral Pupa, smooth, situated obliquelj" upon 

 the spire of the post-nuclear whorls and extending considerabh" be^^ond 

 the lateral outline of this. Post-nuclear whorls rather high between 

 the sutures, somewhat overhanging (this is particularly true of the 

 earlier volutions), slightly shouldered at the summit, ornamented by 

 strong, oblique, rounded axial ribs, which are slightl}- cusped at their 

 posterior extremity, where they show a tendency toward becoming 

 fused; fused at the periphery; twenty-two of these ribs occur upon 

 the first (this whorl is more rounded than the rest and closer ribbed), 

 fourteen upon the second, twelve upon the fifth, sixteen upon the tenth, 

 and twent}' upon the penultimate whorl. The intercostal spaces are 

 twice as wide as the ribs, decidedl}- depressed, smooth, terminating- at 

 the fusing point of the ribs on the peripher}'. The summits of suc- 

 ceeding whorls fall somewhat anterior to the periphery of the preceding- 

 whorl and give the whorls an overhanging efl'ect as well as a narrow 

 smooth ))and between the anterior termination of the intercostal spaces 

 and the subchanneled sutures. Periphery and base of the last whorl 

 well rounded, the latter very short, marked only by faint lines of 

 growth. Aperture very large, almost circular in outline, outer lip 

 thin, transparent, showing the external sculpture within; columella 

 thin, curved and revolute, with a slight oblique fold near its insertion; 

 parietal wall covered by a mere film of callus. 



