SPIROLOCULINA DORSATA. Ill 



Spiroloculina Soldanii, Fornasini, 1886. Boll. Soc. Geol. Ital., vol. v, pp. 183, 



185, Nos. 46, 156, 157; and 1894, 

 Coll. Soldani, &C., 1 pp. 20 and 31, 

 pi. 1, figs. 1, 1 a. 

 — limbata (?) = DOR8ATA, de Amicis, 1893. Ibid., vol. xii, fasc. 3, 



pp. 20, 178, 179. 



— cfr. limbata, a" Orb., de Amicis, 1893. Ibid., vol. xii, p. 310. 



— planulata, Goes, 1894. K. Svensk. Akad. Handl., vol. xxv, p. 107, 



pi. xviii, figs. 836, 836 a. A variety of 

 dorsata, inclining to canaliculata. 



— — — 1894. Ibid., vol. xxv, p. 107, pi. xviii, figs. 



836 b, 836 c. 

 limbata, Goes, 1894. Ibid., figs. 837 and 837 a. 



Characters. — Sutures limbate, periphery plane, somewhat concave. Other 

 limbate forms are the narrow and almost excavate Sp. Lapugyensis and cavernosa, 

 Karrer, 1867 (' Sitzb. Ak. Wien,' vol. lv, pp. 357, 358, pi. ii, figs. 2 and 3). 



Von Reuss, in 1866, replaced Bornemann's appellation "limbata" by 

 "dorsata," because d'Orbigny had already used the former. As the name dorsata 

 has been applied by Reuss to two figures representing Spiroloculina canaliculata 

 and Sp. excavata in von Schlicht's ' Foram. Septarienthones Pietzpuhl,' 1870, 

 pi. xxxvii, tigs. 27 — 32, possibly he regarded these as synonyms. 



Figs. 8 a, 8 4. — Spiroloeidina dorsata, Reuss. a. View of the complete test, with its limbate sutures. 

 b. Edge view from the oral end, showing the square periphery. x 15 (After Brady, ' Challenger ' Report, 

 pi. ix, figs. 17 a, b.) 



The name dorsata seems to be more applicable to canaliculata : and Reuss may 

 have associated the limbate and channelled forms, as was done in Part I of this 

 Monograph, 1866, p. 16. The two together might be diagnosed thus : margins 

 of the chambers more or less limbate, with the shell-growth either marking the 

 sutures, or thickening the outer margins only, and thus fluting the periphery ; 

 centre of shell somewhat hollow. 



In Spiroloculinse having the surfaces of the chambers hollowed or concave 

 there is usually some amount of either sutural or marginal iimbation, which causes 



1 C. Fornasini, ' I Foraimuif'eri della Collezione Soldani relativa al " Saggio Orittografico," 

 esistente nel Museo Paleoutologico del R. Istituto di Studi Superiori in Firenze ; con una Tavola,' 

 8vo., Bologna, 1894, p. 32. 



