2 THE VOYAGE OF H.M.S. CHALLENGER. 



their very close alliance to the fossil genus OrhltoUtes, originally established Ijy Lamarck 

 in his Systeme des Animaux sans Vertebres (1801), on the basis of a well-known 

 fossil of the Calcaire Grossier, which he placed among his " Polypiers Foramines," 

 between Lunulites and MiUepora, giving the following as its diagnostic characters : — 

 " Polypiarium lapideum, liberum, orbiculare, planum seu concavum, utrinque vel 

 margine porosum, nummulitem referens. Fori minimi, adamussim dispositi, conferti, 

 interdum vix conspicui." These bodies, he says, are distinguished from Nummulites by 

 the opening of their marginal pores, and by the absence of any spiral arrangement in their 

 minute chambers or cells. In his Histoire Naturelle des Animaux sans Vertebres 

 (1816-1822), which ranks as a second edition of the preceding, Lamarck altered the name 

 of this type from OrhitoUtes to Orhulites ; but as the latter designation had been previously 

 applied to a Molluscan genus, the original one was restored by M. Milne-Edwards, in the 

 posthumous edition of Lamarck's great work which he edited in conjunction with M. 

 Deshayes. Under one or the other of these names, the genus was accepted by almost every 

 systematist of repute as a Zoologist or a Falseontologist ; but no one gave any account either 

 of the internal structure of the calcareous disk, or of the animal that forms it ; or made 

 any essential modification in Lamarck's definition of the genus, which all left in the 

 place he had assigned to it : — even Dujardin, who first recognised the true zoological 

 position of tlie Foraminifera (which had been ranked, up to his time, as a peculiar 

 group of Cephalopod Mollusks), speaking unhesitatingly of the Orbitolite-disk as a 

 polypary, and of the animals which formed it as polyjjes. It seems to have been by 

 Defrance (Diet, des Sci. Nat., tom. xxxvi., 1825, pp. 294, 295) that the existence, 

 on the coast of New Holland, of a recent tyiie closely resembling the fossil OrhitoUtes 

 of the Paris basin, was first publicly stated, probably on information obtained from 

 MM. Quoy and Gaimard. 



The existence of a recent form of OrhitoUtes of far smaller size and much simpler 

 structure than the fossil OrhitoUtes complanata had, however, been previously indicated 

 by Lamarck in his second edition ; where he defines it under the specific name mav- 

 ginaUs, as OrhitoUtes utrinque plana, margine poroso, speaking of it as found attached 

 to fuci, corallines, &c., in the Mediterranean. This type was carefully studied by M. de 

 BlainviUe, who expressed himself (o^x cit., p. 412) as almost convinced that these small 

 calcareous disks are not true polyparies, but internal pieces, increasing at their 

 circumference. It is evident, he says, that there are no true polype-cells ; but he speaks 

 of " deux plans de locules c[ui occupent le bord," and says that " tout le reste est convert 

 d'une legere cr6ute cretacee, qui ferme les anciens pores." Being well acquainted with 

 the Mediterranean specimens to which these remarks apply, I can well understand how 

 M. de BlainviUe came to overlook the single row of true marginal pores, and to regard 

 as genuine " les deux plans de lociiles " which they very frequently present, but which 

 are the result of the abrasion of their edges. That Lamarck's little OrhitoUtes marginalis 



