TRANSACTIONS OF THE ROYAL MICRO- 

 SCOPICAL SOCIETY. 



DESCRIPTION OF PLATES VIII, IX, X, XI. 



Illustrating Mr. Hogg^s paper on the Lingual Membraties of 

 Mollusca, and their Value in Classification. 



[It should be understood that the arrangement of the pkites in no way 

 serves to indicate Troschel's classification ; the collection of specimens, 

 although large, was found to be inefiicient for the purpose. The descrip- 

 tious are taken in the order of numbering, and as the illustrations were 

 arranged by the artist.] 



PLATE VIII. 

 Tseuioglossa (For. 3—1—3). 



1. — lo. {melania) spinosa, U.S. Specimen prepared and mounted in glyce- 

 rine by Dr. Troschel. Median reflexed and cuspid, central cusp 

 prolonged, with four shorter on either side. 1st lateral broad, top 

 reflexed and denticulate; shaft narrow. 2ud narrow, reflexed, 

 denticulate. Another of the family Melaniadse, PI. IX, fig. 18. 



2. — Bilhinia tentaculata, Suffolk. A small and narrow band, not more 

 than a tenth of an inch in leigth. Median produced outwards, 

 reflexed, denticulations numerous. 1st lateral reflexed, denticu- 

 late. 2nd and 3rd narrower, and finely denticulate. 



3. — Litorina niece, Brit. A small and narrow band. Median produced 

 outwards, reflexed, denticulate ; centre cusp long. 1st lateral widens 

 out at top, reflexed, denticulate. 2nd lateral smaller, denticulate. 

 3rd simple, hooked, slightly produced base. 



4. — Cyclostoma carinatus, Mauritius. Median bold and slightly produced, 

 reflexed ; centre cusp strong and apical, with two or three on 

 either side. 1st lateral resembles median ; cusps not so bold. 

 2nd lateral reflexed and denticulate. 3rd reflexed, numerous den- 

 ticulations. 



5. — Ct/clostoma elegans, Brit., N.B. Median approaching the pyramidal 

 form, reflexed, denticulate; centre cusp rather long. 1st lateral 

 produced outwards, reflexed ; centre cusp strongly apical, with 

 two or three smaller on either side. 2nd lateral narrow, not so 

 much produced, denticulate. 3rd finely serrated ; more properly, 

 uncini numerous. 



