ROTALIA ORBICULARIS. 331 



Eotalina Beccaeii, Egger, 1893. Abb. k. Bayer. Ak. "Wiss., vol. xviii, p. 420, 



pi. xix, figs. 25—27. 

 Rotalia Beccaeii, Be Amicis, 1893. Boll. Soc. Geol. Ital., vol. xii, p. 455. 



— — Fomasini, 1894. Foram. Coll. Soldani, Sagg. Oritt., pp. 11, 



12, and 19. 



Characters. — Shell composed of four or five convolutions. Superior (spiral) 

 surface more or less convex or conical ; inferior, convex or flattened. All the 

 chambers are visible on the spiral surface, the last convolution only on the lower. 

 Septal lines usually limbate and hyaline on the spiral surface ; irregularly excavated 

 and obscured by granulation on the inferior face. Aperture single, simple, on the 

 inner margin of the terminal chamber. 



Our figure of the edge view of Rotalia Beccarii (PI. II, fig. 21) is scarcely 

 characteristic. It appears to have been drawn from a point not exactly perpen- 

 dicular to the transverse axis of the shell, and in consequence the spiral side is 

 flatter and less distinctly trochoid than is usual in good specimens. Prof. 

 Williamson gives admirable and characteristic figures in his ' Monograph' (pi. i\ r , 

 figs. 90 — 92) ; and to these, as well as to his detailed history of the species, we 

 would refer those who desire fuller information in respect to it. 



Occurrence. — Rotalia Beccarii is essentially a shallow-water form, of temperate 

 and tropical seas. It is most frequently met with at depths down to 50 fathoms ; 

 but specimens were found by the 'Challenger' at depths so great as 2950, and 

 by the ' Gazelle ' at 2416 fathoms. 



Fossil specimens have been recorded from the Upper Jurassic of Russia 

 (Uhlig, 1883) ; the Neocomian (Bargate Beds of Surrey) ; the Chalk of Taplow 

 and Ireland; the Eocene (London Clay and Thanet Sands) ; the Miocene of Italy, 

 Malaga, and Vienna ; the Pliocene of Italy and St. Erth ; and the Pleistocene 

 generally. We have also specimens in our own collection from the Casterlian and 

 Scaldisian of Antwerp. In the Coralline Crag it is of very frequent occurrence, 

 and we have specimens from every zone examined. It is also a common form in 

 the Upper Crag, as recorded in the First Part of the Monograph. 



2. Rotalia orbicularis, d'Orbigny, 1826. Woodcut, figs. 24 a, 24 6. 

 Part I, 1866, Appendices I and II, Tables, No. 89. 



Pulvis testaceus ex microscopicis testis, &c, Soldani, 1780. Saggio Orittogr., 



p. 110, pi. viii, figs, aa, AA, BB 

 (= Oyroidina laevigata, d'Orb.). 



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