ORTHOCERAS. 143 



that ; — (1) Walilenberg's species is slightly described and not figured ; but no fossils 

 are now found in Sweden with the slender filiform siphuncle of which he speaks, 

 but only with a broad beaded one ; (2) These latter are the fossils identified with 

 it by Hisinger, and they appear to be quite distinct from the Devonshire shell on 

 account of the obhquity of their septa, and the very excentric position of the 

 siphuncle ; (3) Under these circumstances Foord, at Lindstrom's suggestion, 

 sinks Wahlenberg's description and treats the species as 0. imbricatum, Hisinger/ 

 and places it under the genus Actinoceras on account of its large siphuncle ; (4) 

 In this species he also places 0. pseudo-imbricatum, Barrande,^ leaving 0. imbri- 

 catum, Barrande,^ apparently without a name : (5) 0. imbricatum, Sow.,* in 

 Murch. ' Sil. Syst.,' he places as a synonym of 0. joerversum, Blake/ According 

 to his description this species has deeper chambers than ours has. (6) 0. imbri- 

 catum, Blake,® he places as a synonym of 0. Marloense, Phillips.'' This has also 

 deeper chambers than ours ; and, as far as can be judged from the slight 

 descriptions by Foord, neither of them corresponds with it. (7) Finally he 

 places 0. imbricatum, Phil., ' Pal. Foss.,' with a " ?" under Actinoceras Soiverbiji 

 (M'Coy)^ =■ 0. unduJatmn, Sow.,^ ' Min. Conch.' (not Schlotheim nor Phillips). 



This/ last identification, however, is apparently wrong ; for the septa do not 

 appear to form a sinus in Phillips's species, and the siphuncle seems much smaller 

 and nearly if not quite central. It is, however, apparently rather large, so that 

 the shell may possibly prove to belong to the genus Actinoceras, although from 

 the evidence at present existing this is most improbable. Unfortunately, Mr. 

 Champernowne's specimen has lost the central part in slicing, and the siphuncle 

 does certainly seem to be slightly on one side along the shorter diameter. 



Kayser^'^ figures, apparently without any description, a longitudinal section of 

 an Orthoceras, which, though larger, closely corresponds with the English fossils 

 in the width of its septa and the contour of its sides. The lowest part of its 

 septal chambers is perhaps rather more central. 



In 0. angustiseptatum, Giimbel," which is the same as 0. gregarium, Miinst.'" (not 



1 1831, Hisinger, ' Anteckn. Physik. Geogn.,' pt. v, p. 112, pi. iv, fig. 4. 



2 1866, Barrande, ' Syst. Sil. Boheme,' vol. ii, pt. 3, p. 705, pi. ccxxviii, fig. 1 ; pi. ccxxxiii, figs. 

 4 — 8 ; and pi. cccexl, figs. 1, 2. 



2 Ibid., p. 701, pi. cccexl, figs. 3, 4. 



* 1839, Sowerby in Murch., ' Sil. Syst.,' p. 620, pi. ix, fig. 2. 



5 1S82, Blake, ' Mon. Brit. Foss. Ceph.,' pt. 1, p. 155, pi. xvi, figs. 1, 2. 



6 Ibid., p. 153, pi. xiv, figs. 1, 3—6. 



' 1848, Phillips, ' Mem. Geol. Surv.,' vol. ii, pt. 1, p. 353, pi. iii, fig. 1. 



8 1855, M'Coy, ' Brit. Pal. Foss.,' pt. 3, p. 573. 



9 1814, Sow., ' Min. Conch.,' vol. i, p. 130, pi. lix. 



10 1878, Kayser, 'Abhandl. Geol. Specialk. Preussen,' Band iv, pt. 2, pi. vi, fig. 7. 

 " 1879, Giimbel, ' Geogn. Beschr. Konig. Bayern,' pt. 3, p. 498. 

 12 1840, Miinster, ' Beitr.,' pt. 3, p. 97, pi. xviii, fig. 1 b. 



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