FORAMINIFERA FROM THE NORTH ATLANTIC AND ARCTIC OCEANS. 
358 
Lagena sulcata , Walker and Jacob, Yar. (Entosolenia) Melo, D’Orb. Plate XIII. figs. 
33-36 (Arctic). 
This is L. sulcata with a modified ornamentation. It has small transverse ridges 
between the ribs, connecting them, and forming subquadrate reticulations, which vary 
in different specimens. 
Professor Reuss would retain Williamson’s term catenulata for those specimens that 
have the cross-bars weaker than the ridges; probably a convenient, though hardly 
necessary, arrangement ; the modifications of the relative thicknesses of the longitudinal 
and transverse ridges are endless, varying from a network of thin lines, equal or unequal 
in strength, to that with broad, flat, equal ridges, and shallow squarish pits between. 
Further, our figs. 33-36, Plate XIII., show sufficiently clearly that no characteristic can 
be found in the disposition of the secondary or transverse riblets, whether end to end, 
or alternately between contiguous ribs ; for in the same specimen they vary as regards 
this arrangement. 
Fig. 34 has but few of the cross-bars, and these are oblique. In this it not only con- 
nects L. sulcata with L. Melo by the presence of secondary riblets, but the obliquity of 
these connecting bars shows a tendency towards the formation of the variety L. squamosa , 
next to be described, in which the ornament has a honeycomb- rather than a ladder- 
pattern. Dr. Wallich figures another pretty passage-form, ‘ North- Atlantic Sea-bed,’ 
pi. 5. fig. 23. 
Figs. 33 & 35 differ in the relative size of the areolse ; a condition dependent upon 
the number of the primary ribs, and very variable. From the Hunde Islands, 30-70 
fathoms; and from the Arctic Ocean (mixed sands). 
Fig. 36 is an extremely rare monstrosity, being a Lagena with a superadded chamber. 
It is from the Hunde Islands, from between 30 and 40 fathoms, shelly muddy sand 
(Dr. P. C. Sutherland). This specimen is unique in our collection. Soldani has 
figured a specimen extremely like this one, in his ‘ Testaceograph.’ vol. i. part 2, pi. 95. 
fig. A ; named Nodosaria cancellata by D’Orbigny (Ann. Sc. Nat. vol. vii. p. 254, No. 29). 
As a rule, monstrosities of the Lagena are formed by the budding, as it were, of a 
new chamber obliquely on the side of the original chamber (Plate XVIII. figs. 10-12); 
these are very rare. If, however, a smooth or ribbed Lagena were to take on an addi- 
tional chamber in the axis of the primary chamber, it would be scarcely distinguishable 
from a Nodosaria. We possess such a form (from the shallow water at Eastbourne), 
Plate XVIII. fig. 9, which we believe to be a monster of Lagena Icevis. In the Tertiary 
Sands of Bordeaux also, rich with Lagence and small Nodosarice , very puzzling forms 
occur, which may either be two-celled individuals of Nodosaria scalaris, Batsch *, or 
possibly monstrous varieties of Lagena sulcata. In the specimen before us (Plate XIII. 
fig. 36) we have a mode of ornamentation never found in any Nodosarian Foraminifer; 
* Well figured by Wallich in ‘ The North- Atlantic Sea-bed,’ pi. 5. fig. 18, and in Journ. Sci. No. 1, Jan. 1864, 
fig. 6, in the plate illustrating his paper on the bed of the Atlantic Ocean. Figured also, for comparison, in 
our Plate XVIII. fig. 13. 
