XXVI. Researches on the foraminifera

Abstract

78. History .—The interesting group of organisms belonging to this type seems to have early attracted notice, probably on account of the great abundance in which it presents itself on the sands of many of the West Indian shores. Three species are described and figured by Fichtel and Moll, under the names of Nautilus orbiculus , N. angulatus , and N. aduncus . Lamarck, however, in his first systematic treatise, separated them from Nautilus , and raised them to the rank of an independent genus, to which he gave the name of Orbiculina ; and he also changed two of the specific names, the three standing respectively as O. numismalis , O. angulata and O. uncinata . By Denys de Montfort, these species were raised to the rank of independent genera, under the names of Helenis , Archaias , and Ilotes ; but these genera have not been adopted by any other systematist. M. d’Orbigny, in his first classification of the Foraminifera, not merely adopted Lamarck’s generic designation, but affirmed that the three reputed species were really nothing else than one and the same organism in different phases of growth, O. angulata being the youngest, O. numismalis the next in age, and O. uncinata the adult. He arrived at this result, of the truth of which I am myself well assured, by the comparison of a great number of specimens, —a process which it would have been well for science if he had more constantly adopted. The name of the adult form should of course stand as that of the species; but the organism in question is more commonly known under the designation Orbiculina adunca , which seems to have been conferred upon it by M. Deslongschamps. 79. A considerable number of figures of this species are given by M. d’Orbigny in his treatise on the Foraminifera of Cuba, which forms part of the great work of M. Ramon de la Sagra on the Natural History, &c. of that island. These figures, however, serve only to give a general idea of the diversities of external conformation which had presented themselves to him; and notwithstanding their number and variety, they do not include some of the most important among the protean shapes of these bodies, nor do they throw any light upon their internal structure.