314 Mr. H. J, Carter on the Structure of the Foraminifera. 



been removed by acid, remains in connexion with the membranous 

 chambers by short branches, through which globular bodies (to 

 which I shall more particularly allude presently), that are more 

 or less present in the chambers, readily pass, on pressure, into 

 the larger interseptal canals ; and again through these, probably 

 by the openings on the spicular cord, during the living state, 

 they would have obtained an exit. That the sarcodc of the 

 canal-system also carries on the development of the organism 

 independently of the chambers, is proved by the development of 

 the test continuing after the chambers have ceased to be formed, 

 as will also be hereafter mentioned. 



Lastly, the substance covering the horizontal surface of the 

 test, which I have likened to the cuticle of shells, in accounting 

 for the formation of the horizontally-laminated structure of the 

 test, and have inferred to be connected with the sarcode of the 

 chambers through its vertical tubuli, MM. d'Archiac and Haime 

 have more properly likened to the " epiderme des echinides ou 

 de l'epitheque des polypes" (p. 69). But what I meant is seen 

 by the context in my paper, viz. that, in its dry state, it was 

 merely like the cuticle of shells in appearance, and not identical 

 with it. 



Of this substance Dr. Carpenter states nothing in his paper 

 on Operculina; but in his description of Orbitolites he observes, 

 in a foot-note (p. 207), " I have little doubt that ' the greenish ' 

 cuticle described by Mr. Carter as covering his Operculina ara- 

 hica, and supposed by MM. d'Archiac and Haime to be specially 

 connected with the formation of the shell, is of the same nature/' 

 that is, of the nature -of "a covering of vegetation, chiefly com- 

 posed of Diatomacese, Desmidiere, and other minute Algas." To 

 which I must simply reply that " such a mistake is impossible 

 with a practical microscopist." Moreover, lately I have had to 

 examine some " deep-sea soundings " from the Arabian Sea, in 

 which there were many minute Foraminifera ; and as it is at 

 such depths that the Foraminifera are most likely to be taken up 

 alive, or with the living sarcode of the animal in their tests, so 

 most of these were covered with the so-called " cuticle" first seen 

 on the substance of Operculina arabica. 



But are not the horizontal or " spiral " laminse (as they have 

 been termed by D'Archiac and Haime, in Nummulites) of Oper- 

 culina composed almost entirely of vertical tubuli which establish 

 a direct connexion between the cavity of the chambers and the 

 surface, and between the chambers of the overlying layers in 

 Nummulites ? Is not the sarcode which fills the cavities of the 

 test of Operculina, &c, like that of the Rhizopoda generally, 

 whose portions flow together when they come in contact ; and 

 would they not thus form a layer over the surface of the 



