213 
species varies from five to seven, but without reference to sex. 
The very close agreement both in the lingual teeth and in the 
general internal anatomy of Fusus and Buccinum was men- 
tioned, 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 to be so 
placed; but, judging from the general character of their 
teeth, he thought they might possibly remain with the 
Scutibranchiata, or perhaps it would be necessary to establish 
a new order expressly for them. 
Professor Williamson 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 specimens of tongues from thirty different species of 
Gasteropoda, with the shells from which they were extracted. 
One of the lingual ribands was two and a half inches long. 
