114 F0RAMIN1FERA OF THE CRAG. 



limbata, pointing out that that author had published a good limbate form, and 

 that this name, as generally used, was applied by d'Orbigny to an unsatisfactory 

 specimen of a different kind figured by Soldani (see above, p. 33). He also 

 indicated that the chambers are not at all depressed as in Bornemann's figures, 

 and in the limbate form of " depressa" figured by Williamson (' Recent. Brit. 

 Foram.,' p. 82, fig. 177). 



Following the artificial grouping explained at page 103, we see that the 

 Spiroloculina shown by PI. V, fig. 3, is not planulata, for it has not flat, but 

 somewhat convex or slightly turgid, chambers ; nor are they hollowed or 

 depressed along their length, as is usual in canaliculata and dorsata. Whether or 

 no the outer margins of the earlier chambers were limbate (those edges being now 

 covered up) need not affect the question of the relationship of this from the 

 Crag, and the other from the ' Challenger ' dredgings. Had Dr. Brady given a 

 name to his specimens we should have adopted it. It is evidently a limbate 

 subvariety of nitida, d'Orb., which is a subtype or variety of the type Spiroloculina 

 planulata (Lamarck). 



The form under notice has some allies in Terquem's Spiroloculina angulifera, 

 ' Mem. Soc. Geol. France,' ser. 3, vol. ii, p. 156, pi. xxiv, figs. 11 and 12 (with their 

 associates among figs. 10 — 15) ; and Sp. alata (in part), ibid., p. 158, pi. xxiv, 

 fig. 18. Schwager's Sp. desertorum and proboscidea were very near allies to our 

 fig. 3. 



Occurrence. — Spiroloculina nitida,. This varietal form of Sp. planulata is 

 common in tropical waters and in the Mediterranean. It has been noticed fossil 

 in the Jurassic (Terquem), the Cretaceous (Wizniowski), and the Tertiaries of 

 Hungary, Germany, Italy, and France. In the Crag it has been found only at 

 Sutton. 



Note. — (1) Mr. Millett has enumerated in the following lists several other 

 forms of Spiroloculina. Some of these are characterised by the chambers being 

 angular on the exterior surface. Of these the best type, in his opinion, is Sp. 

 acutimargo, Brady. 



Spiroloculina Poetanana, d'Orbigny, 1839. Foram. Cuba, p. 168, pi. x, figs. 1,2. 

 OiiNATA, d'Orbigny, 1839. Ibid., p. 167, pi. xii, fig. 7. 

 TENUinosTRA, Karrer, 1867. Sitz. k. Akad. Wiss. Wien, vol. lv, 



Abth. 1, p. 358, pi. ii, fig. 5. 

 dispahilis ?, Terquem, 1878. Mem. Soc. Geol. Fr., ser. 3, vol. i, 



p. 55, pi. x, fig. 12. 

 affixa, Terquem, 1878. Ibid., fig. 13. 

 angulosa, Terquem, 1881. Plage Dunkerque, fasc. 3, p. 132, 



pi. xvii, fig. 9. 

 laminata, Terquem, 1881. Ibid., p. 133, pi. xvii, fig. 11. 



