OF CONCHOLOGY. 23 



After such conclusive facts, we think it unnecessary to insist 

 further on this point. 



In the system of classification proposed by Mr. Morch, for 

 Geophiles or Terrestrial Mollusks provided with lungs and with- 

 out operculge, a system based exclusively on the form of the 

 jaws, we see that the genera Clausilia, Pupa and Cylindrella 

 (Urocoptis) are placed each in a different division, the first in 

 the Ozi/gnatha, the second in the Aulacognatha, and the third 

 la the Agnatha. This strange result we believe is of such a nature 

 as to inspire legitimate doubts of the value of the system to any 

 one who knows how very similar these three genera are, not only 

 by the ensemble of their conchological characters, but still more 

 by the general appearance and the manner of living of their Mol- 

 lusks, conchologicallyspeaking; their relations are so intimate that 

 there are certain dubious forms, which have been bandied about 

 by authors between the three genera, or at least between two of 

 them. In a zoological point of view, the similarities between 

 the animal of the Pupa and that of the Clausilia are numerous, 

 and as for their way of living, in both genera are found rock 

 species (having usually a whitish shell) who brave the heat of the 

 sun, and species with almost subterraneous habits. Concerning 

 the organization of the Cylindrella, information is very scarce ; 

 nevertheless, the animal of the species figured by Guilding and 

 Swainson is small, short, and looks very much like that of the 

 Clausilia. The absence of jaw should need to be confirmed by 

 researches made with care. As for the similarity of the lingual 

 dentition that Mr. A. Schmidt believed he perceived in the Cylin- 

 drella and the Testacella, it is more apparent then real, at 

 least as far as we can judge by the little personal observations 

 that we have been able to make. Thanks to an obligino; com- 

 munication from Mr. Thomas Bland, we have been able to exa- 

 mine the lingual band of the Cylindrella sca^va, Gundlach, of 

 Cuba. The only similarity that we have found to exist with 

 that of the Testacella consists in the oblique position of the 

 lateral teeth, and it is that which probably caused Mr. Schmidt 

 to commit an error. 



But as to the structure of these teeth themselves, it is totally 

 different, and does not at all resemble the spinulae, so character- 

 istic of the Testacellce.* 



* These teeth resemble much more those of the Limax, Ariolimaz, Anadenvs, 

 &c., although, however, this resemblance is not identical. The central formula 

 of the Cylindrella scxva is 13.1.13. The central tooth is straight, small, and 

 furnished with a very prominent median point. The lateral teeth are placed 

 obliquely, large, bicuspid, and with a square base. Both points are not placed 

 on the same plane. The five last teeth diminish as to their volume, and their 

 two points become less and less apparent, but their general form remains 

 always the same. H. Obosse, 



