382 
MR. W. K. PARKER AND PROEESSOR T. R. JONES ON SOME 
both in this arrested Truncatuline variety and in the outspread Plano rbulince. Two 
young individuals, establishing themselves close to each other, grow on until their shells 
become blended and confused ; this is still better seen in the many-chambered Planorbu* 
linee , two or more of which, growing into each other, form lichen-like patches on shells. 
Plate XVI. figs. 18-20 (North Atlantic). 
Truncatulina lobatula belongs essentially to shallow waters, and it becomes smaller 
when in deeper water than usual (as is the case with the specimens before us), and is 
then more compact and neat, takes on a limbation (exogenous edging to the chamber- 
walls, fig. 19), and soon approaches the conical and shapely Tr. refulgens , Montfort, sp. 
On the eastern marginal plateau of the North Atlantic Truncatulina lobatula is 
common and of middle size at from 43 to 78 fathoms, rare and small at 338 fathoms. 
It is absent from the abyssal depths. To the north of Newfoundland Bank (“Arctic” 
tract) it is rare and small at 145 fathoms, and rare and middle-sized at 740 fathoms. 
Planorbulina farcta, Fichtel and Moll, sp., Var. Haidingerii , D’Orbigny, sp. Plate XVI. 
figs. 22 a, 22 b (North Atlantic). 
This is a variety of Planorbulina farcta near to PI. lobatula , but biconvex and having 
more chambers and a more solid and symmetrical make. It is usually larger and more 
ventricose than these Atlantic specimens. 
This and PI. TIngeriana are two closely allied, compact, and flush-chambered varieties 
of PL farcta, more Rotaliform than PL lobatula ,. and inhabiting moderately deep seas.. 
In the North Atlantic PL Haidingerii is rare and of middle size at 1776 fathoms in the 
Abyssal area. It is more abundant in the “ Virginian Province ” on the coast of New 
Jersey (see page 333 and Appendix II.). The two are fossil together in Tertiary beds. 
PL Haidingerii is world-wide, like the type, and bears the same relation to it that 
Eotalia Soldanii does to P. Peccarii, — a rather large and moderately deep-sea variety. 
Planorbulina farcta, Fichtel and Moll, sp., Var. TIngeriana, D’Orbigny, sp. Plate XVI. 
figs. 23-25 (North Atlantic). 
This variety has relatively narrower chambers and more limbation than its congener 
Pl. farcta, var. Haidingerii, D’Orb., sp., above-mentioned. 
It is widely distributed in the Atlantic. On the marginal plateau off the Irish coast 
it is rare and small in the shallow, common and largest in the deeper parts. In the 
Abyssal tract (“Celtic”) it is common but small ; and throughout the “Boreal” portion 
of that tract (1400-2300 fathoms) it is rare and small. It is figured in Dr. Wallich’S 
‘North-Atlantic Sea-bed,’ pl. 6. figs. 20, 21. 
P i TIngeriana is world-wide, like the last ; but, as a weaker and smaller shell, it 
takes the place of the type in deepest waters, where also Potalia orbicularis represents 
P. Peccarii. Pl. Culter, nov., Plate XIX. fig. 1, is a rare, keeled subvariety, living at 
great depths. 
