Dr. J. E. Gray on the Tongues of Mollusca. 411 



XXXIX.— On the Tongues of Mollusca. By J . E. Gray, Ph.D ., 

 F.R.S., V.P.Z.S. &c. 



Lister, Leeuwenhoek, Swammerdam, Poli, Cuvier, Fleming, 

 Berkeley (Zool. Trans, iv. 278), Osier (Phil. Trans. 1832), Quoy 

 and Gaimard*, Delle Chiaje, Alder and Hancock, and some other 

 naturalists, have at varied and distant periods described and 

 figured the tongues of difi'erent isolated species of Mollusca. 



In 1836 Dr. Troschel (Wiegmann's Arch. 1836, 257. t. 9 & 10) 

 published an essay, describing in systematic order and figuring 

 the jaws and tongue of various species of the land and freshwater 

 Mollusca of Germany ; unfortunately the figures are very small 

 and indistinct. 



In the volume of the same work for 1839 (v. 177. t. 5. f. 8) 

 he described and figured the teeth on the tongue of Amphipeplea 

 of Nilsson, and proposed to form the family L/ymneadce into two 

 groups, according to their teeth, thus : A. Physa and Amphi- 

 peplea, B. Planorbis and Lymnea ; and in the volume for 1845 

 (xi. 197. t. 8. f. 6) he gives a description of the anatomy of the 

 animal, and especially of the teeth on the tongue of Ampullaria 

 urceus. 



It is to be observed that all these observations are confined to, 

 aud give a very good connected view of, the teeth in the terres- 

 trial and fluviatile Mollusca. 



In 1847 Dr. Loven (Ofversigt af Kongl. Vetensk. Acad. For- 

 handl. 1847, 175) describes and figures the teeth on the tongue 

 of the several orders, families,- and genera of Mollusca. The 

 figures are all drawn on the same plan, and with great distinct- 

 ness and accuracy. He divides the tongues he has seen into 

 fourteen groups, and separates the genera into families and sec- 

 tions characterized by the position and form of the teeth. 



The groups he has formed are exceedingly natural, and this 

 paper, like his work on the Scandinavian Mollusca, opened a new 

 field of observation to the naturalist. 



In the following year Dr. Troschel, in the third edition of 

 Wiegmann and Ruthe's ' Handbuch der Zoologie,' Berlin, 1848 

 (a work, only the first edition of which has come into my hands ; 

 there is however an abstract of the arrangement in Wiegmann's 

 Archiv, 1849, 84), proposed a new arrangement of the Gaste- 

 ropodous Mollusca, characterized by their sexual peculiarity, the 



* The figures of the teeth by these authors are, like many details in 

 French scientific works, not given with sufficient care to be of much use. 

 They figure the teeth of the male and female Strombus Lamhis, t. 49. 

 f. 20 ? , t. 50. f. 8 (? , quite imlike each other ; and their figures of the 

 teeth of Ampullaria, Mitra, and other genera arc so indistinct as to be of 

 little use for scientific purposes. 



