REPORT ON THE FORAMINIFERA. 
519 
nearly as indistinct and theoretical as in the latter. Lingulina and Frondicularici form 
a continuous series, including the compressed and complanate straight Nodosarince. To 
the former genus are assigned those forms which have directly transverse or arched septa, 
to the latter those in which the segments are bent in a greater degree. The extent to 
which the segments are reflexed varies with almost every species. In what may be looked 
upon as the typical Frondicularian shell, that in which the generic peculiarities are 
developed the most fully, the chambers are prolonged backwards at the two sides so far 
that each encloses the whole, or almost the whole, of its predecessor. 
The surface of the test is either smooth or has a superficial ornament of longitudinal 
strise or costse, either continuous or interrupted; and occasionally the sutures are marked 
by raised lines of shelly deposit. 
The genus Frondicularia is subject to dimorphous modification in two ways. Some- 
times the earlier chambers are developed on one side only, so that the shell has a 
planospiral or Cristellarian commencement, whilst the later segments take the normal 
shape and arrangement. Such varieties constitute the subgenus Flabellina. On the 
other hand, the early segments may be Frondicularian and the later ones cylindrical or 
Nodosarian, and these forms have been distinguished under the subgeneric name 
A mphimorphina. 
Recent Frondicularia are exceedingly rare. If we except a comparatively small area 
in the western portion of the Atlantic, from the West Indies northward to Bermuda, and 
a limited region of the Indian Archipelago, south-west of Papua, it is impossible to name 
any ground on which hitherto more than a chance specimen or two has been met with. 
The depth of water which the genus most affects appears to be from 80 to 600 fathoms. 
As a fossil type Frondicularia is much more adundant, and its range in geological time 
extends from the Trias to the later portion of the Tertiary epoch. 
Frondicularia spathidata, H. B. Brady (PI. LXV. fig. 18). 
Frondicularia spatlmlata, Brady, 1879, Quart. Journ. Micr. Sci., vot xix., N. S., p. 56, pi. viii. 
fig. 5, a.b. 
Test elongate, narrow, tapering, compressed ; lateral edges rounded and somewhat 
lobulate ; segments numerous ; sutures slightly excavated. Primordial segment inflated ; 
those immediately following it more reflexed than the later chambers, which are only 
slightly curved. Surface smooth. Length, J r yth inch (0'56 mm.). 
This is one of the narrow compressed Nodosarian shells that might with almost equal 
propriety be placed either with Lingulina or Frondicularia , the slightly inflated 
primordial chamber and bent earlier segments suggesting somewhat greater affinity to the 
latter genus. 
