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
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