Occasional Papers of the Museum of Zoology 69 



than in the other subspecies; spiral sculpture of low, weak, 

 rounded to subangular ridges, which are often obsolescent, 

 and are scarcely surmounted by the growth threads; inter- 

 sections without cusps. Earlier whorls : closely-spaced, growth 

 sculpture obscures the weaker, spiral ridges. Subapical 

 whorls : like fossor. Umbilicus : even less hidden by the 

 peristome than in westpuntensis. Aperture : internally light 

 orange to dark chocolate, usually vivid orange; spiral bands 

 inconspicuous. Peristome: quite deeply but gradually ex- 

 panded ; internal callus quite heavy, continuous. Other char- 

 acters as in fossor. 



Measurements 

 Shell Aperture Operculum Whorls 



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

 male 13.0 65( 8.4) 52(6.7) 51(6.6) 91(6.0) 35(4.5) 73(3.3) 31/2 

 male 13.7 63( 8.6) 50(6.9) 48(6.5) 91(5.9) 36(4.9) 74(3.6) 3y2 

 female 

 (type) 16.2 62(10.0) 50(8.1) 47(7.6) 95(7.2) 33(5.3) 76(4.0) 4 



A2ab. Common (200 specimens collected). Type lot (see Table VII) ; 

 many specimens have the spiral sculpture considerably reduced (fig. 

 xiii— 5 ) , 



A2c. Quite common; under limestone slabs (161 specimens). Slightly 

 larger, but otherwise typical. 



Al. Quite infrequent; under limestone slabs (129 specimens). 

 Bleached; almost half of the shells uniform whitish to pinkish. Heavier, 

 with more prominent sculpture, and with especially well-developed 

 peristomal callus. 



This subspecies is, by itself, distinct enough to be a separate 

 species, but the next form, which is plainly a geographical 

 variety of it, is so close to westpuntensis that it was thought 

 best to regard all of the Aruba specimens as subspecies of 

 fossor. 



Tudora fossor canashitensis, new subspecies 



Type locality: (A4b) top of Seroe Canashito, Aruba. 



Distribution : Aruba ; limestone rim from Spaansch Lagoen 

 and Boedoei north ; narrowly invades region of older rocks at 

 the Hooiberg (A3-8). Under rocks; a distinctly terrestrial 

 form. 229 specimens collected. 



