292 Zoological Society : — 



markings is so wide (as is proved by the gradational transitions 

 which present themselves between what at first sight appear to be 

 widely-separated types), that only where some very decided and con- 

 stant difference of internal conformation presents itself, will it be safe 

 to assume a specific diversity. In one case, in which he had thought 

 that a certain series of specimens was sufficiently distinguished 

 by its peculiar physiognomy from the rest, residual forms presented 

 themselves which could not be with certainty assigned to either 

 type, so completely do they link together the two by the softening 

 down of the peculiarities of each. And a yet more remarkable link 

 of connexion is established by examples collected on the coast of 

 Japan by the American expedition to that country, in which the 

 most distinctive characters of each type are curiously combined. 



Closely related to Operculina is another genus, Amphistegina, 

 which bears an equally near resemblance to Nummulites, though it 

 has been completely separated from both in the classification of 

 M. d'Orbigny, who has placed it in a distinct order, Entomostegues, 

 on account of the unsymmetrical form of its shell and the alternating 

 disposition of its chambers. But the author has found, from an 

 extensive comparison of individuals, that this want of symmetry is so 

 little constant, as to be altogether valueless in a systematic point of 

 view, many specimens being perfectly symmetrical, whilst others 

 are very far from being so, and every gradation presenting itself 

 between these two extremes. The most common among existing 

 species is the Amphistegina gibbosa, which is very extensively dif- 

 fused through the tropical ocean, and which, though generally of 

 small size, acquires in the Philippine region dimensions nearly equal 

 to those of the fossil Amphistegina of the Vienna and other tertiary 

 deposits. But Mr. Cuming's Philippine collection contains another 

 and far larger species, which is distinguished by the extraordinary 

 thinning-out of the last whorl ; and it is remarkable that in this 

 species the canal-system is highly developed, although completely 

 absent in A. gibbosa, — a difference of structure, which, being asso- 

 ciated with a very close resemblance in external aspect and general 

 conformation, seems only to be accounted for on the supposition that 

 the difference in size requires a difference in the arrangement of the 

 nutrient apparatus. 



ZOOLOGICAL SOCIETY. 



March 9, 1858.— Dr. Gray, F.R.S., V.P., in the Chair. 



Proposal to separate the Family of Salamandrid^e, 

 Gray, into Three Families, according to the form of 

 the Skull. By Dr. J. E. Gray, F.R.S., V.P.Z.S., Pres. 

 Ent. Soc, etc. 



In the Catalogue of Amphibia in the British Museum I placed 

 all the Salamanders which have teeth on the inner side of the hinder 

 edge of the palatal bone together in a single family, under the name 

 of SalamandridcB. 



