THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY, 



[SECOND SERIES.] 

 No. 57. SEPTEMBER 1852. 



XV. — On the Form and Structure of the Shell of Operculina 

 Arabica. By H. J. Carter, Esq., Assistant Surgeon, Bom- 

 bay Establishment. 



[With a Plate.] 



The interest which attaches to the forms and structure of Fora- 

 minifera is naturally very great, for no one can have seen their 

 beautiful little shells and the extensive tracts in the Nummulitic 

 series, which are almost entirely composed of their remains, 

 without wishing to know something of the animals by which 

 they were constructed. 



Fortunately many are now living to help us out in this re- 

 spect, and although for the most part very small, yet, here and 

 there are found some sufficiently large, as will hereafter be seen, 

 to afford us almost all the information we could expect to obtain, 

 were the fossil species even living, in their largest forms. 



In the month of June 1847, I communicated a paper to the 

 Bombay Branch of the Royal Asiatic Society, containing, among 

 other observations, a summary up to that time of all that was 

 known of the structure of Foraminifera ; and by way of intro- 

 duction, as well as for the purpose of rendering this paper more 

 complete and more useful, I will here insert the latter, adding 

 what has been done since, and then a description of the form and 

 structure of the shell of Operculina Arabica, which will, I think, 

 elucidate all that has hitherto been stated of, and leave little to 

 be added to, the general structure of Foraminiferous shells, both 

 recent and fossil. 



" For ten years after D'Orbigny gave his description of the 

 animal of Foraminifera, no one appears to have taken much 

 trouble to question its accuracy, until Dajardin took up the 



Ann. ^ Mag. N. Hist. Ser. 2. Vol.x. 11 



