NODOSARIN &. 57 
DrnTaLina communis, D’ Orbigny. 
Under the name of Wadosaria (Dentalina) communis D’Orbigny has placed two varie- 
ties of smooth, tapering, curved Wodosarie, one having straight and the other inclined 
septa. Both of these conditions (the septal planes being in one case at right angles to 
the axis of the shell, and in the other oblique) occur together in very many specimens of 
such Dentaline, and therefore can be accepted only as artificial means of distinction. 
Moreover, the relative length and convexity of the segments are extremely variable, even 
in one and the same specimen; and the length, also, and curvature of the shell, and its 
departure from the cylindrical form, are all unstable characters. It results that all these 
varieties (almost as numerous as the individuals) can be grouped either under “Vodosaria 
dentalina’ of Lamarck, or the better known name “ Dentalina communis,” D’Orbigny. For 
convenience, we may keep the oblique-chambered specimens erp enas from the others 
when it preponderates over the other character. 
The modifications of the Dentaline having straight septa are more numerous than the 
others, as the latter, or oblique forms, soon become more definitely characterised as 
“Vaginuline” and “Marginuline.” 
There are, however, other varieties of smooth Dentaline, many specimens having 
globose chambers (D. radicularis, Mister, &c.), and others having swollen but long 
segments (D. globifera, Batsch, &c.). 
These smooth Dentaling are really tapering and curved sub-varieties of Modosaria 
radicula ; the ornamented individuals belonging to JV. raphanus; and the obliquity of 
the segments and departure from axial symmetry culminating in the closely coiled and 
discoidal Cristellaria. 
Among the numerous Dentaline sub-varieties of Modosaria raphanus (Dentalina 
obliqua, Linn., being the first in order) every modification of JV. raphanus has its Dentaline 
representative, whether the riblets be general or partial, few or many, coarse or fine, 
straight or oblique, continuous or interrupted, obsolete or replaced by spines or granules. 
So also there are Vaginuline, Marginuline, Cristellarian, Frondicularian, and other modifi- 
cations, respectively smooth (after the habit of JV. radicu/a and its congeners), or orna- 
mented (after any of the patterns adopted by JV. raphanus in its variations). As Marginulina 
raphanus is the central form of all these modifications of one type, we have chosen it (as 
Nodosarina raphanus, typica) as the zoological representative of the group. 
It is inconvenient at present to construct a scheme of the alliances of the chief 
Nodosarine forms; and even for the odosari@ alone it would be almost a vain labour to 
attempt it, as they all mutually graduate one into the other—G/landinuline, Linguline, 
Dentaline, Vaginuline, Marginuline, &c., having full participation in all the characters 
8 
