126 TUE NAUTILUS. 



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heen described, and various obscure question in phylogeny and 

 classification have become more clear to nie. It is my purpose to 

 discuss these matters in a series of short papers. 



Fischer has divided the suborder Geophila (=Stylommatophora) 

 or stalked-eyed Pulmonates into two main branches, Monotremata 

 and Ditremata. It seems to me that a more fundamental sejiaration 

 is indicated by the presence or absence of a jaw, together with the 

 modifications accompanying this character. I would therefore 

 primarily divide the land pulmonates into Agnatha and Guatho- 

 phora. 



SUPERFAMILY AgKATHA. 



No jaw; teeth of the radula arranged in very oblique V-shaped 

 rows, all of them of the aculeate or thorn-shaped form, the side-teeth 

 larger than the central tooth, which is often obsolete. 



The families of Agnatha are as follows.^ 



I. Mantle small, posterior ; shell rudimentary or developed ; a 

 common genital orifice Testacellidce. 



II. Mantle enveloping the whole upper surface ; no shell ; genital 

 orifices separated Rathouinidce. 



The last named family is identical with the genus Vaghmlus as 

 understood by Stoliczka and Binney ; not Vaginulus Fer., which as 

 Ferussac himself says lias a jaw. Veronicella Blainv. and authors, 

 is the same as Vagimdus Fer. 



The Rathouisiidce have been found only in India and China. 



The TestacellidcE comprise a great variety of forms. The family 

 is practically world-wide in distribution in tropical and subtropical 

 regions. 



Genus Glandina Scluim. 



Additional species and varieties. 



G. truncata Gm., form ovaia Dall. A short form, measuring 44 x 

 25 mm. Pliocene of the Caloosahatchie. 

 How does it differ from hullata Gould ? 



G. truncata Gm., form viacer Dall. Long, narrow, but not parallel- 

 sided, 75 X 20 nun. Recent, and fossil in the Caloosahatchie beds. 

 Like the form parallela W. G. B., these are doubtless only the 



extreme aspects of variation in a very mutable species. 



1 Fischer recognizes but one family, TestacellidcE ; ignoring the agnathous 

 Vacinulus like forms. 



