GENERA CORNUSPIRA. AND NUBECULARIA. 6.9 



where (as already mentioned) a slight constriction marks ofif the primordial chamber at the 

 commencement of the spire. Hence the body will present no appearance of segmentation 

 except at that point, and the large size of the external aperture will enable it to extend 

 its pseudopodia most freely into the surrounding medium. — The Cornuspira foliacea, which 

 is at present the only known form of this type, attains the diameter of l-8th of an inch. 



85. Affinitlea. — In CornusjnrH we have a sort of rough sketch of the higher type of 

 helicine Foraminifera, which it greatly resembles in external form, but from which it differs 

 in the simplification of its structure resulting from the absence of segmentation in its sarcode- 

 body. Its growth, like theirs, is unlimited; and thus, although actuallj/ monothalamous, 

 it may be considered ixs /loteiilialli/ polythalamous (^ G2). 



86. Geot^raphical and Gcolot/ical Distribution. — This type is at present very generally 

 diffused through various seas, its shells growing attached by one of their lateral surfaces 

 to Alga; and Zoophytes, usually at no great depth. It has not been met with in any 

 formation of older date than the Eocene; but it abounds in the "calcaire grossier," and 

 presents itself at every subsequent epoch. 



Genus III. — NuBECUL.\RiA (Plate V, figs. 1 — 15). 



87. Hislof!/. — The genus Niiheadana was first established by Defrance (xxix) for the 

 reception of an assemblage of small calcareous bodies of variable form and extremely indefi- 

 nite characters, which he found within univalve shells of the " calcaire grossier." He expressed 

 himself as altogether undecided in regard to the place to be assigned to them in the animal 

 series; but in figuring them he grouped them with Zoophytes (xxix, Zooph., PI. xliv, fig. 3). 

 A comparison of the figures given by him (imperfect as these are) with the figures previously 

 given by Soldani (ci) of certain of the bodies to which he gave the general designation Serpula, 

 serves to show that this type had been previously recognised by that painstaking observer. 

 The indefiniteness of Defrance's characterisation of the genus seems to have prevented its 

 adoption by subsequent authors ; thus we find that even Blainville did not accept it (vi a), 

 though retaining Defrance's figures and the name appended to them on the plate ; and 

 Lamarck makes no mention of it. The genus was entirely ignored by M. D'Orbigny, though 

 one of its multiform varieties was described and figured by him under the name Webhina riigosa 

 (v, PI. i, figs. 16 — ^18, and Lxxiii, p. 74, PI. xxi, figs. II, 12). It has, however, been noticed by 

 M. Dujardin (xxxviii), who remarks of it that its proper place is probably rather among Fora- 

 minifera than among Polypifera. The firm establishment and true characterisation of the genus, 

 however, can only be fairly attributed to Messrs. Parker and Rupert Jones, by whom it has 

 been especially studied in its recent as well as in its fossil forms (lv, p. 455), and who have 

 kindly furnished me with the materials on which the following account of it is based. 



88. External Characters. — No Foraminiferous shells are more protean in shape than 

 those of Nubecularia, for we find them presenting almost every plan of growth that is to be 

 found among Foraminifera. It is one of their distinctive characters that they attach themselves 

 to other bodies, the surfaces of which they use as part of the walls of their own cavities ; and 



