212 



is an interesting subject, he should endeavour to bring it 

 before the next meeting. 



The discussion *'0n the cause of metallic lustre upon the 

 wings of the Lepidoptera" was resumed. Mr. Latham 

 stated that he saw no reason to alter the views he had ex- 

 pressed ; but since the last meeting Mr. Watson had called 

 his attention to an article in the *^Annales des Sciences 

 Naturelles" for February, 1835, by Bernard Dechamps, "Sur 

 les Ailes des Lepidopteres/' which contains much information 

 upon the scales and the cause of their brilliance; he (Mr. 

 Latham) had translated and printed extracts from the paper ; 

 copies were handed round to the members present, and may 

 be had (gratis) at the Society's rooms, or from the Secretary 

 of the Microscopical Section. 



A Paper was read by Dr. Thomas Alcock *' On the 

 Tongues of Mollusca." 



The Author remarked upon the great variety and beauty 

 of these objects, and pointed out their scientific value as a 

 help in the classification of shells. On investigation the 

 tongues were shown to arrange themselves into four groups, 

 according to the pattern or type of the lingual dentition, and 

 these groups were stated to correspond with four of the orders 

 established by Cuvier, on the characters of the breathing 

 organs. The four orders illustrated ■were the Pectinibran- 

 chiata, the Scutibranchiata, the Cyclobranchiata, and the 

 Pulmonata; and he believed that, on the evidence of the 

 teeth, it will be necessary to re-establish the order Cyclo- 

 branchiata as distinct, instead of including jt in the 

 Scutibranchiata, as is done by our latest authorities. 



The Author had examined many specimens of Buccinum 

 undatum of both sexes, a series of which were exhibited to 

 prove that the number of points on the central teeth in this 



