50 FORAMINIFERA OF THE CRAG. 



Dentalina STRiATissiMA, StacJie, 1865. Novara-Exped., Geol. Tlieil, I Band, II Ab- 



theil., p. 200, pi. 22, fig. 38. 

 NoDosAKiA (Dentalina) Ludwigi, Reuss, 186(). Denks. Math. -Nat. CI. Akad. Wissen., 



vol. XXV, p. 19, pi. 2, fig. 23. 



Charciciers. — Shell straight, subcylindrical, tapering, composed of a few largish 

 cliaiubers, and externally ribbed from end to end by stont parallel ridges. The con- 

 strictions marking the septal lines are sometimes concealed by the overgrowing longi- 

 tudinal costse. Liable to become either curved or compressed, or both, vi^ith more or less 

 excentric aperture ; and thereby passing into either Dentalina or Marginulina. 



Length ~\X\ to :;th inch and more. 



It would be impossible to define exactly the limits between Nodosaria raphanus and the 

 two forms which follow it on our list, N. raphanistrum and N. scalaris. All are straight 

 Nodosarians, and have longitudinal costse. That there is a considerable amount of 

 varietal distinction, the examination of a few specimens of each would satisfy any observer, 

 and is confirmed by the peculiarities of distribution. In general terms, we may say that 

 the species now under consideration {N. raphanus) is the bold, few-chambered, coarse- 

 rilibed, and tapering form ; N. raphanistrmn is a longer and more cylindrical shell, with 

 ii larger number of segments, and the ribs more neatly put on ; and N. scalaris is a few- 

 chambered, more delicate, and transparent shell, seldom growing to a large size, and 

 commonly having an extended neck produced from the terminal chamber. 



A specimen from Sutton (Lower Crag) and one from Thorpe (Upper Crag) are the 

 only evidences we have of this species in the Crag ; nor is it an abundant form anywhere, 

 except in the Adriatic, where it is frequently Marginuhniform (like our fig. 21), and is 

 associated with arcuate or Dentaline varieties. 



In the Lias clays N. raphanus is sparingly found where the other Nodosarincs are very 

 common ; and in other Secondary and many Tertiary formations it is to be met with. 



Professor Williamson figures a broken specimen (fig. 43) from the British seas, but 

 does not give the locality ; and we have one or two examples from deep water (70 to 

 80 fathoms) off Shetland, and several from a similar or greater depth in the Hebrides. It 

 occurs in the North Atlantic (78 fathoms) ; South Atlantic (Abrolhos Bank, 260 fathoms) ; 

 and in the Mediterranean and Adriatic seasj but well-developed specimens are rare. 



2. NoDos.uuA RAPHANisTRU.M, Linn., sp. Plate I, figs. G — 8. 



Nautilus KAPHANisTKUM, izn«., 1758. Syst. Nat., 10th ed., p. 710, No. 242 ; 1767, 



Syst. Nat., 12th ed., p. 1163, No. 282. 

 Nautilus costatus, var., Montagu, 1808. Test. Brit. Supp., p. 83, pi. 19, fig. 2. 

 Orthoceua iiAPHANiSTitUM, Lamarck, 1822. An. s. Vert., p. 594, No. 3. 



— -De Blainville, 1824. Diet. Sc. Nat., vol. xxxvi, p. 486. 



NoDOSAKiA Bacillum, Be/rance, 1825. lb., vol. x.xxv, p. 127 ; vol. xxvi, p. 487, Atlas 

 Conch., pi. 13, fig. 4. 



