OF OONCHOLOGY. 169 



REVIE'W. 



Notes on Lingual Dentition of 3folIusca. By W. G. Binkey and Thomas 

 Bland, An. Lye. Nat. Hist. N. Y. Vol. IX, pp. 281—294. February, 

 1870. 



BY WM. H. DALL, 



It is now twenty-four years since the appearance of a paper 

 by Dr. Lov^n, on the classification of the mollusca by their lin- 

 gual dentition, marked an era in malacological science. Long 

 before, in the days of Adanson, and even before that time, the 

 teeth with which some of the commoner species are furnished, 

 had been noticed by observing students, but no investigations of 

 practical importance preceded those of Loven and Troschell. 

 Since that time the progress of this branch of the science has 

 been slow but sure ; and the great advances made are only ap- 

 parent by comparison. While the claims of some of the more 

 enthusiastic of its early advocates have hardly been realized, yet 

 the character of the dentition, to-day, is accepted by the best au- 

 thorities as one of the most important and reliable aids to the 

 proper classification of species and genera. 



In the present paper, figures are given of Succinea Nuttal- 

 liana, Lea, Bulimulus pallidior, Sby., " Helix " tiimida, Pfr., 

 Zonites Icevigata^ Pfr., Veronicella fioridana. Bin., Lvnax jiavus, 

 Lin., Melampus bidentatus, Say, Helicina occulta, Say, Pom- 

 pholyx effusa, Lea, Planorhis trivolvis, Say, and Tulotoma mag- 

 nifica, Conrad. 



The method of obtaining these figures, as stated by Mr. Bin- 

 ney before the Boston Society of Natural History a few months 

 ago (Oct. 1869) was as follows : A microphotograph was taken, 

 from the ribbon itself, upon a glass slide. This negative was 

 then placed in a magic lantern and the magnified image thrown 

 upon a sheet of white paper suspended on the wall, and the out- 

 lines then traced with pencil upon this paper. These outlines 

 were then photographed upon the block, to be engraved. The 

 sun, as Mr. Binney remarked, thus doing all the work, it was 

 reasonable to suppose that the results would defy criticism. 



The photography was done by Mr. Powel, and the tracing by 

 Mr. Binney, in person ; Mr. Bland, as we believe, not being re- 

 sponsible for any of this work, and consequently not responsible 

 for the character of the figures. We believe that Mr. Binney 

 has been conscientious in his work, and that the errors which we 



