THE JAW AND LINGUAL MEMBRANE. 41 



duced by foreign shipping, probably around water-casks. It is also well 

 known to have been introduced into other countries. The Limaces 

 are found around human habitations ; they seem to follow the English 

 to all their colonies. The other foreign species mentioned on p. 36 

 have probably been introduced around the roots of plants, as have been 

 other species which are from time to time sent me from greenhouses, 

 gardens, etc. They are only local, except Tachea hortensis, which may 

 have been accidentally introduced in some other manner, since the dis- 

 covery of America by Europeans, and owes its present distribution in 

 the Northeast to its being peculiarly adapted to colonization. I have 

 elsewhere related my successful attempt to colonize the allied Tachea 

 nemoralis} 



III. THE JAW AND LINGUAL MEMBRANE. 



In Volume II. my father paid great attention to the jaws and lingual 

 membranes, figuring those of all the species which he could obtain. In 

 continuing my father's labors on the same subject, I had described and 

 figured those of many other species. Thus, in a certain sense, it could 

 be said that a great deal w^as known of these organs in our land shells. 

 Unfortunately, however, these figures and descriptions had become of 

 comparatively little value when the study of this subject had assumed 

 such importance as of late. They did not give in sufficient detail the 

 character of the individual teeth, however correct an idea they may 

 have given of the general arrangement of the teeth upon the mem- 

 brane. I was, therefore, induced to review the whole subject, and pre- 

 sent it in a manner which would be of value as throwing light upon 

 classification, in the Proc. Ac. Nat. Sc. Phila., 1875, pp. 140-243. 



In their proper places under each genus and species will be found 

 below the result of my re-examination of the subject. I will here repeat 

 in full some general remarks on the organs treated of, and on their 



retain a strong odor of the p;arlic which seasoned them for the foreign palate. I have my- 

 self had specimens given me by French residents of the town where I reside, who had 

 bought them as food in Philadelphia. The species has also been imported into Havana, 

 Rio Janeiro, St. lago, Chili, and other ports as an article of food. I found numerous liv- 

 ing specimens in St. Michael's churchyard in Charleston, S. C, in 1875, and in 1871 Pro- 

 fessor Featherman sent me specimens from Baton Rouge. 



1 See below, under T. hortensis, in the descriptive portion of the work. 



