48 University of Michigan 



Tudora aurantia wassauensis, new subspecies 



Type locality: (B8) Seroe Wassau, just west of entrance to 

 the Goto, Bonaire. 



Distribution: Bonaire; northern portion, south to the Goto 

 (at least) and east to the cliffs near Fontein (B6, 8, 9; Bb9). 

 Klein-Bonaire: (Kl), Quite abundant in similar habitats to 

 aurantia, also in favorable valleys in the higher hills of the 

 older rocks ( Bb9 ) . 597 specimens collected. 



Shell (fig. xii-B) : heavier and slightly larger and more 

 slender than aurantia. Growth sculpture (fig. x-28) : con- 

 siderably heavier, higher, and more widely spaced, so as to 

 expose the distinctly marked spiral sculpture. Peristomal 

 callus : heavier. Other characters as in aurantia. 



Measurements 



Shell Aperture Operculum Whorls 



alt. maj.diam. min.diam. alt. diam. long wide 



male 13.5 56( 7.5) 45(6.1) 40(5.4) 78(4.2) 31(4.2) 78(3.3) 5 



female 18.8 56(10.5) 47(8.8) 39(7.4) 80(5.9) 28(5.3) 85(4.5) 514 

 female 



(type) 18.2 57(10.4) 46(8.4) 40(7.2) 83(6.0) 29(5.3) 85(4.5) 5% 



B8. Quite abundant (155 specimens collected). Typical lot (see 

 Table V). 



B6. Very common (13 specimens). Somewhat smaller. 



B9. Very infrequent; mainly on Cereus and under rocks at the base 

 of these cacti. Bb9. Eare (141 specimens altogether). Somewhat 

 smaller. The specimens from Seroe Grandi (B9) are bleached, and quite 

 commonly stained with a rusty deposit, as appears characteristic of speci- 

 mens of Tudora from these wind-swept, excessively arid places. Growth 

 sculpture widely spaced but lower; scarcely more prominent than the 

 spiral; the entire shell distinctly cancellate. 



Kl. Very common (288 specimens). Large and heavy; somewhat 

 bleached. Altogether more or less intermediate between wassauensis and 

 aurantia, this lot from Klein-Bonaire is considerably closer to the for- 

 mer; this is especially peculiar as the conditions are similar to those in 

 the type locality of aurantia, just across the harbor. 



Although this subspecies intergrades with typical aurantia, 

 large lots give an impression of a markedly more costate shell. 

 In the typical lot of wassauensis, the growth sculpture is rela- 



