AURIS-GONYOSTOMUS. 121 



goniostoma. The hydrophanous zigzag lines are seen in no other 

 species of Auris. 



The minute papillose sculpture is the same as that of A. midas, 

 but coarser. The spire is somewhat costulate, there is no trace of 

 spiral sculpture, and the lip is sinuous; it therefore appears that A. 

 haiunvelli is a member of the group of A. distorta, rather than of the 

 A. goniostoma group in which there is distinct spiral sculpture, non- 

 costulate and longer spire, and the lip is not sinuous. 



A. hauxicelli is one of the most peculiar and beautiful species of 

 the family Bulimulidce. 



Subgenus GONYOSTOMUS Beck, 1837. 



( Gonyostomus or Goniottomus plus Anthinus Alb. For refer- 

 ences see p. 96). 



Shell riraate-umbilicate, fusiform or ovate-conic, with 5-5 gently 

 convex whorls. Surface finely granose spirally. Aperture elliptic 

 or ovate, angled above, rounded below, or angular at base also ; the 

 peristome evenly, narrowly expanded or reflexed ; outer lip evenly 

 arcuate, not sinuous, with no internal callous projection; columellar 

 lip free, inserted high, the columella with a deep-seated and weak 

 fold. Type A. goniostoma. 



Distribution, south-eastern Brazil. 



Gonyostomus differs from Eudolichotis in the system of sculpture 

 and in having an evenly arcuate peristome, in a level plane, the lip 

 neither sinuous nor with callous thickenings within. The union of 

 A. goniostoma with the distorta group, and of A. perdix and midas 

 with A. multicolor, on account of the angulation or roundness of the 

 bases, is a thoroughly unnatural grouping. A. multicolor is closely 

 allied to hybrida and goniostoma in sculpture, color, texture, and 

 characters of the aperture, while A. perdix and midas are closely 

 connected with the didorta group by intermediate species. Both 

 Eudolichotis and Gonyostomus include species with angular and 

 species with rounded bases. This feature is no more a group charac- 

 ter in Bulimoid shells than the angulation of the periphery is in 

 Helices; and the reference of all forms having the base angular to 

 one subgenus is as artificial an arrangement as the Lamarckian 

 " genus " Caracolla for all keeled Helices. 



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