J('V HYPERAULAX. 



This species has not been figured. It is readily distinguishable 

 from dsedaleus, patagoniciis and dentatus by its narrower form, more 

 regular striation and more numerous teeth. 



Genus HYPERAULAX Pilsbry, 1897. 



Proc. Acad. Nat. Sci., Phila., 1897, p. 10; Man. of Conch, xi, p. 

 82 (as a section of Bulimulus). Includes Bonnanius Jouss., see 

 below. 



Shell umbilicate, ovate, with 4^-5^ whorls, the apex sculptured 

 with waved wrinkles. Aperture about half the total length, having 

 a callous nodule at the posterior angle, more or less separated from 

 the end of the lip by a groove; peristome reflexed, unarmed [or in 

 the section Bonnanius having vertical upper palatal and columellar 

 teeth, and usually two teeth (angular and infraparietal) on the 

 parietal wall]. Soft anatomy unknown. 



This group was formerly subordinated to Bulimulus, but I am 

 now convinced that it belongs in the immediate neighborhood of 

 Anctus and Odontostomus. The group probably was an early branch 

 from the Odontostomine stock before it had split into the modern 

 genera Anctus, Odontostomus, and Tomigerus. 



The infraparietal lamella is the longest of those on the parietal 

 wall, when any are present. This agrees with Plagiodontes and 

 Tomigerus; while in other Odoniosto mince having lamella; on the 

 parietal wall, the parietal is longest. In Tomigerus the parietal 

 lamella is small, in Hyperaidax (Bonnanius) it is wanting. Anctus 

 laminiferus has a vertical, not entering, tooth upon the outer lip, 

 analogous to, possibly homologous with, that of Hyperaidax ramagei. 

 Until we know something of the pallial, muscular, digestive and 

 genital systems of Tomigerus, Hyperaidax and Anctus, their mutual 

 relations cannot be adequately understood. 



Dr. O. von Mollendorff has recently (Nachr. d. D. Malak. Ges., 

 1901, p. 12G) suggested that B. ridleyi belongs to the Buliminoid 

 group Napceus, directing attention to its similarity to species of the 

 A/ores; but the latter do not have the apical sculpture of Hyperaidax 

 ridleyi, and I regard the resemblance as a case of convergent evolu- 

 tion, perhaps due to some similar insular environmental factors, and 

 not of phylogenetic significance. 



The typical section of the genus includes the recent species H. 

 ridleyi (Smith), of Fernando Noronha (Manual xi, p. 82), and the 



