The wooded lower mountain slopes, chaparral-covered 

 hills, and grassy valleys compose the Upper Sonoran Zone, 

 belt of Big-cone Douglas Spruce, California Walnut, Live Oak, 

 Canon Oak, Wild Lilac (Ceanothus spinosus), Manzanita (Uva- 

 ursti tomentosa, U. pungens), Birch-leaf mahogany, Chamise 

 (Adenostoma fasciatum), California Bay, White Alder, Mari- 

 time Prickly-pear, and Sycamore, which forms the great bulk 

 of the Los Angeles System. Landshells are frequently rare, 

 particularly in the more arid portions, and hardly ever abund- 

 ant, but, as landshells go in southern California, this zone fur- 

 nishes the most accessible and prolific collecting. All the large 

 helicies, several minute species, and the introduced forms are 

 restricted within its limits. 



The following are found : 



-Agriolimax hemphilli -Glyptostoma newberryanum 



f ?Amalia hewstoni ffHelix aspersa 



::: ?Anadenulus cockerelli ffLimax flavus 



Ariolimax columbianus ffLimax maximus 

 -Bifidaria calamitosa Punctum californicum 



*Bifidaria Clementina Punctum conspectum 



*Bifidaria hemphilli ' -Pupa sterkiana 



*Binneya notabilis Pupoides chordata 



f Circinaria duranti f Succinea oregonensis 



-Circinaria transfuga fSuccinea sillimani 



f Epiphragmophora areolata f Vallonia pulchella 

 fE. areolata crassula fVertigo californica 



*Epiphragmophora ayresiana :: ?V. californica catalinaria 



*Epiphragmophora gabbi *?V. californica diegoensis 



*E. gabbi rufocincta *?V. californica elongata 



-"Epiphragmophora intercisa ffVitrea cellaria 

 -Epiphragmophora kelletti -Vitrea diegoensis 

 *E. kelletti tryoni Zonitoides arboreus 



fEpiphragmophora traski fZonitoides milium 



fEpiphragmophora tudiculatafZonitoides minisculus 



The Lower Sonoran zone, belt of Fremont Cottonwood, 

 Dudley's Willow (Salix vallicola), Bebbia, and the Cacti (ex- 

 cept the maritime Prickly-pear), of the arid flood plains and 

 valley bottoms contains, so far as known, no land shells. 



SYSTEMATIC CATALOG-. 



*The general arrangement proposed by Pilsbry, (Naut. XI, 1897, p. 

 45 ff) is adhered to in the following pages with the exception of the 

 grouping of the Arionidae and Pupidae, subsequently revised by Pilsbry 

 and Ferris (Proc. Phila. Acad. Nat. Sci., 1898. p. 226 ff and 1900, p. 

 582 ff), which classification is adopted. 



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