PROCEEDINGS OF SOCIETIES. 129 



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 establislied by Cuvier, on the 

 characters of the breathing organs. The four orders illustrated were 

 the Pectinibranchiata, 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 Cyclobranchiata 

 as distinct, instead of including it 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 species varies, 

 from five to seven, but witliout reference to sex. The very close 

 agreement both in the lingual teeth and in the general internal 

 anatomy of Fusus and Buccinum was mentioned, and a doubt was 

 expressed as to the propriety of their wide separation in our present 

 systems of classification. The association of Fusus with Murex, and 

 of Purpura with Buccinum, was also commented upon, and shown 

 by the evidence of the tongues, as well as the general anatomy of 

 the animals, to be clearly incorrect. 



In conclusion, some remarks were made on the method used by 

 the author, of extracting the tongues from the different kinds of 

 mollusca, illustrated by specimens, some of which were many 

 times longer than the bodies of the animals, being coiled up near 

 the neck, and brought forward as the teeth are worn away. The 

 paper was illustrated by beautifully executed drawings of the 

 different types, and a series of dissected animals. 



Professor Williamson asked the author if he proposed to include 

 the Chitons in the order Cyclobranchiata. 



Dr. Alcock was satisfied the Chitons ought not be so placed ; 

 but, judging from the general character of their teeth, he thought 

 they might possiby remain with the Scutibranchiata, or, perhaps, 

 it would be necessary to establish a new order expressly for them. 



Professor ^Villiamson was glad to learn that this was the result 

 of Dr. Alcock's observations ; for the animals certainly appeared 

 very distinct, and the Chitons, which he remarked have the form of 

 a gigantic woodlouse, were evidently not Cyclobranchiata, as they 

 have a separate gill down each side of the body. 



On adjourning to the microscopes. Dr. Alcock exhibited mounted 

 spcimens of tongues from thirty diff'erent species of Gasteropoda, 

 with the shells from which they were extracted. One of the lingual 

 ribands was two and a half inches long. 



jMr. Latham exhibited scales from the wings of the Catarrhactes 

 papua, a Penguin from the Falkland Islands, which appear to be 

 intermediate between feathers and scales. 



