MUSEUM OF COMPARATIVE ZOOLOGY. 217 



" You are right in saying that the slit in the mantle extends to the back margin. 

 The central pit seems flooded with mucus at all times, but does not change its 

 form ; the slit, however, seems to widen and show a little ridge on either margin 

 when the animal is fully expanded. The little tubercles, or small pimples as it 

 were, seem to cover the posterior portion of the mantle, while the elongated tuber- 

 cles seem to cover the anterior half, though these at times disappear and the ante- 

 rior portion runs into folds, which break up the surface, and starting from the 

 margin of the mantle run to its centre in parallel lines like miniature waves. 

 They move steadily inward from both margins, disappearing before reaching the 

 little mucous pit in the centre of the mantle, little wavelets rising at the margins 

 and keeping up a constant rhythmic motion toward the centre." 



The jaw of this specimen has about 25 ribs, denticulating either margin. It 

 is low, wide, slightly arcuate, with slightly attenuated ends. (See Plate IX. 

 Fig. A.) 



The lingual membrane is as described and figured by me in Vol. V. ; tbere 

 are, however, in this form, 57-1-57 teeth, with some eleven true laterals. 



The genitalia I have figured in Plate III. Fig. 3. It agrees with my figures 

 in Vol. V. of the genitalia of the original specimens, excepting that the penis 

 sac, as represented there in Plate XII. Fig. K, is here doubled on itself. 



Pupa hordeacea, Gabb. 



An authentic specimen of this species is figured in the Second Supplement, 

 Plate III. Fig. 10, referred by mistake to P. Arizonensis in the explanation of 

 Plate III. 



Pupa Arizonensis, Gabb. 



The reference to hebes in Second Supplement should be Fig. 12, not Fig. 10. 



LOCALLY INTRODUCED SPECIES. 



Tachea nemoralis, Linn. 



Fine large specimens of this species have been sent me by Prof. James H. 

 Morrison, found by him living during the last three years at Lexington, Vir- 

 ginia. They form part, no doubt, of a colony descended from living individ- 

 uals introduced from Europe around plants. 



Zonites cellarius, Muller. 



Also at San Francisco (Cooper). 



Limax maximus, Linn. 



Also at New Braunfels, Texas (Singerly). 



A drawing of the lingual dentition on Plate II. Fig. 1, shows the cutting 

 points of central and lateral teeth to be trifid. This is not shown in my figure 

 in Vol. V. 



