328 Mr. H. J. Carter on the Structure of the Foraminlfera. 



trated by Dr. Carpenter (Phil. Trans. 1856, p. 552) is totally 

 different from Parkinson and Sowcrby's Fascioliies clUptica, 

 which is the type of the Alveolina of Scinde, and of which I have 

 given illustrations (Ann. Nat. Hist. 1854, vol. xiv. p. 99); while 

 the new species, which I have described further on, under the 

 name of A.meandrina, is again so different from either and from 

 any other existing description, that at first sight it seems doubt- 

 ful whether it should not form the type of a new genus. On 

 examining it internally, however, it is found that its chambers, 

 although tortuous like those on the surface of N. gyzeliensis, &c, 

 commence in a spiral form as simply as those of Operculina, but 

 instead of remaining subsigmoid, as in A. elliptica, become tor- 

 tuous, while there is a reticulated canal-structure arching over 

 each, and supported on vertical tubes connected with a similar 

 structure over the preceding layer, which, when viewed longitu- 

 dinally in a vertical or horizontal section, appears to correspond 

 to the tubular structure arching over the chambers and inter- 

 septal canals respectively of A. elliptica, which structure, again, 

 corresponds, as before stated, to the spicular cord and interseptal 

 canals of Operculina and Nummulites. 



Orbitoides, D'Orb. 



In this family two distinct genera have been included, viz. 

 Orbitoides dispansa and Orbitoides Mantelli, D'Orb. {Orbitoides 

 Mantelli, Cart.), as will be seen by their descriptions hereafter 

 under their respective heads. Moreover, it will also be seen 

 there that they are so different that they can hardly be included 

 even in the same family : at least, while the former is closely 

 allied to Oycloclypeus, Carp., the latter is so closely allied to 

 Orbitolitcs that I proposed the name of " Orbitulitcs Mantelli 31 

 for it, instead of " Orbitoides" (Ann. Nat. Hist. vol. xi. p. 174, 

 1853). Whether this was a better name than its original one 

 (that is, than " Orbitoides Mantelli") I will not stop to discuss 

 now, but go on to notice the structure of these two fossils re- 

 spectively and summarily, referring the reader to a more detailed 

 description of them under their proper heads. The detail of 

 their anatomy has been obtained from richly infiltrated specimens 

 in which, as in the Nummulitc and Operculina mentioned, the 

 red or yellow oxide of iron so completely fills up the cavities of 

 the test which were originally occupied by sarcode, while the 

 rest remains more or less transparent and white, that sections of 

 the fossil in this state give a much better view of these cavities 

 than could be obtained from the test were it present in its un- 

 fossilizcd condition and occupied by the living animal. Follow- 

 ing are the summary descriptions of them respectively. 



Orbitoides dispansa (PI. XVI. fig. 1, &c). — The test of this 



