EXPLANATION OF PLATE 25 

 All figures natural size except where noted 



Fig. 1. Ficus piriformis Gabb. Drawing of back view of imperfect speci- 

 men. Univ. Calif. Loc. 1686. 



Fig. 2. Trophosycon nodiferum (Gabb). Back view of adult specimen, canal 

 lacking. Elsmere Canon, Los Angeles County. 



Fig. 3. Agasoma barker ianum Cooper. Aperture view of immature speci- 

 men without carina or tubercles. Cal. Acad. Sci. Loc. 64. 



Fig. 4. Trophosycon nodiferum (Gabb). Aperture view, showing nodes 

 nearly absent on part of body whorl. Elsmere Canon. 



Fig. 5. Agasoma sinuatum Gabb. Side view, shows carina and general 

 shape well. 



Fig. 6. Agasoma sinuatum Gabb. Aperture view, showing the narrow, deep 

 canal. Univ. Calif. Loc. 1354. 



Fig. 7. Agasoma gravidum (Gabb). Back view; canal broken. From the 

 lowest exposed beds of the Monterey group, Contra Costa Hills. 



Fig. 8. Agasoma gravidum (Gabb). Aperture view. 



Fig. 9. Agasoma barkerianum Cooper, var. clarki new var. Back view of 

 slightly distorted specimen; shows tubercles on anterior part of body whorl. 

 Univ. Calif. Loc 1352. 



Fig. 10. Agasoma barkerianum Cooper, var. clarki. new var. Back view; end 

 of canal and outer lip lacking. Univ. Calif. Loc. 1352. 



Fig. 11. Agasoma barkerianum Cooper, var. santacrusanum Arnold. Back 

 view of specimen with rounded carina, and lacking tubercles on body-whorl. 

 All gradations are found between this form and the one shown in fig. 14. Cal. 

 Acad. Sci. Loc. 64, Barker's Ranch. 



Fig. 12. Agasoma barkerianum Cooper, var. santacrusanum Arnold. X 2. 

 Taken from Arnold, in U. S. Nat, Mus. Pub., vol. 34. 



Fig. 13. Agasoma barkerianum Cooper. Aperture view, showing canal and 

 thick callus. Cal. Acad. Sci. Loc. 64. Barker's Ranch, Kern County. 



Fig. 14. Agasoma barkerianum Cooper. Back view of a typical adult speci- 

 men. Cal. Acad. Sci. Loc, 64. 



[256] 



