274 Messrs. W. K. Parker and T. Rupert Jones on some 



The shell itself may be hyaline and tubuliferousj or opake and 

 homogeneous, or arenaceous, i. e. made up of siliceous or other 

 particles cemented with shell-material. 



Before proceeding with the description of the Foraminifera 

 from Norway, we think it advisable to offer a few succinct re- 

 marks upon the characters of this group of shelled Rhizopods ; 

 referring the reader to Dr. Carpenter's recent memoirs for a 

 fuller consideration of the subject. 



To arrive at a clear idea of the specific relations of the Fora- 

 minifera, we must study these creatures in large numbers ; such 

 as well-arranged and extensive collections of specimens from 

 various seas and harbours, and from numerous fossil deposits, 

 can alone supply. (See Carpenter, loc, cit. § 74.) 



It must be understood that, although among the lowest orders 

 of plants and animals — such as Conferv(je and Diatomaceay In- 

 fusoria and Rhizopoda, — the immense numbers of mere varieties, 

 passing by indistinguishable gradations of shape one into an- 

 other, have been by some authors enumerated as so many spe- 

 cific forms, yet there is no real ground for the establishment of 

 species on these variations of character, which are for the most 

 part merely such difierences among individuals as one finds 

 between the several leaves of a single tree. 



Foraminifera, indeed, are to be compared with the other lowest 

 orders of animals and of plants in the study of their specific 

 relations. In these several low forms of creatures we have com- 

 paratively few species, but extremely numerous individuals, with 

 an enormous range of variety. In the higher orders of plants 

 and animals the specific forms are more definite, there being a 

 more complex organization, harmonizing with the special habits 

 of each creature ; and the individuals of each species are less 

 numerous than is the case in the Protozoans and Protophytes. 



These low animals, the Foraminifera^ having great simplicity 

 of structure, more easily adapt themselves to varying external 

 conditions than the more complex and specialized higher ani- 

 mals (see Carpenter, loc. cit. § 76). Hence the greater immu- 

 nities enjoyed by these Protozoa from the various causes of ex- 

 tinction acting upon the individuals of the higher classes ; and 

 the long existence of several special Foraminifera through nearly 

 all the geological epochs, appears to be in a great degree a con- 

 sequence of this adaptability to circumstances, and the resulting 

 tenacity of existence. 



As these little shelled Rhizopods live under an immense 

 variety of circumstances as to climate, depth of the sea, and its 

 saltness, difi'erent composition of the sea-bed, varieties of bodies 

 to which they adhere, &c., it cannot surprise us that one and 

 the same species should exhibit a great range in variety as to 



