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V.—Notes on Chelonia from the Purbeck, Wealden and London-clay

Published online by Cambridge University Press:  01 May 2009

R. Lydekker  and
G. A. Boulenger
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Extract

Introductory.—The writers having had occasion, in company with Mr. Davies, to examine the greater number of the remains of English fossil Emydine and Pleurodiran Chelonia in the collection of the British Museum, with a view both to their rearrangement in the cases and the determination of their affinities, and having in the course of such examination been enabled to add several genera to the British fauna, as well as to make certain emendations in regard to the age and affinity of some of the previously-described forms, have thought it advisable to put their observations on record.

Type
Original Articles
Information
Geological Magazine , Volume 4 , Issue 6 , June 1887 , pp. 270 - 275
Copyright
Copyright © Cambridge University Press 1887

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References

page 270 note 1 Page 521. I must apologize to M. Dollo for having in this notice misinterpreted him as retaining Prof. Cope's family Propleuridœ. In the same notice I have quoted English forms under the generic names assigned to them by Owen, not having at that time entered on the question of the correctness of their determinations.—[R. L.]

page 271 note 1 See Amer. Nat. vol. xx. p. 968 (1886).Google Scholar

page 271 note 2 Cope (loc. cit.) states that his Propleuridœ is identical with Dollo's Pachyrhynchidœ. The type species of the latter is, however, expressly stated to have only eight costals, which Cope makes a character of Puppigerus.

page 271 note 3 It is usual among English writers to term the bony parts of the Chelonian shell “plates,” and the horny epidermal covering “scutes”; but Prof. Huxley, “Anatomy of Vertebrated Animals,” 1st edition, pp. 197, 200 (1871)Google Scholar, uses the former term for both. Since, however, the term “scute” is applied to the dermal bones of the Crocodilia and of the Armadillos (vide Huxley, , op. cit. pp. 250, 338),Google Scholar which are homologous with some of the bony elements of the Chelonian shell, this use is certainly objectionable; and in previous works I have reversed the application of the two terms. This application is not, however, thought advisable by Mr. Boulenger, who usually employs the terms in their older sense; as a compromise, in the present paper the bony elements will therefore be alluded to as “bones,” and the elements of the epidermal layer as “shields.”-[R. L]

page 271 note 4 Rep. Brit. Assoc. for 1841, p. 164 (1842).Google Scholar

page 271 note 5 Verh. Nat. Ges. Basel, vol. vi. p. 121 (1873).Google Scholar

page 271 note 6 Specimens of Purbeck Chelonia in the Cambridge Museum have been referred by Prof. Seeley, (Index to Aves, Ornithosauria, etc., in the Cambridge Museum, pp. 86, 87 [1869] ) to Pleurosternum, under the names of P. Sedgwicki, P. Vansitturti, P. Oweui, and P. typocardium. These specimens have, however, not been figured, and cannot therefore be compared with those in the British lluseum; some of them may perhaps belong to Plesiochelys, while the distinction of others from P. Bullocki is not clear.Google Scholar

page 272 note 1 Proc. Amer. Phil. Soc. 1882, p. 143.Google Scholar

page 272 note 2 The presence of an intergular shield is distinctly mentioned on page 5 of Owen's “Wealden and Purbeck Reptilia,” although it is not shown in a complete state in any of the figured specimens.

page 272 note 3 Mr. Boulenger takes this view.—[R. L.]

page 272 note 4 Neue Denks. schweiz. Ges. Nat. vol. xxv. pls. xii. xiii.Google Scholar

page 272 note 5 Ibid. pl. xi.

page 272 note 6 Verh. Nat. Ges. Basel, , op. cit. p. 166.Google Scholar

page 272 note 7 Wealden and Purbeck Reptilia, pls. viii. and ix.

page 273 note 1 Bull. Mus. R. Hist. Nat. Belg. vol. iii. p. 78 (1884).Google Scholar The name itself is not very happily selected, since Prof. Seeley (Quart. Journ. Geol. Soc. vol. xxxvi. p. 412, 1880), has proposed the name Peltochelyidœ for an entirely different group of Chelonia.Google Scholar

page 273 note 2 Geology of S.E. of England, p. 255 (1833)—Trionyx. Tretosternum punctatum, Owen, dates from 1842.Google Scholar

page 273 note 3 Rep. Brit. Assoc. for 1811, pp. 165–7Google Scholar (1842). Sir R. Owen's words are, “The entire and rounded margins of the truncated and expanded extremities of the ribs, beyond which there is not the slightest trace of projecting tooth-like processes, strongly indicates that the marginal plates [bones] were either wanting or rudimental, as in the genus Cryptopus [Trionyx].”

page 273 note 4 Op. cit. p. 167. The generic name was given upon the assumed existence of this feature; since, however, the vacuity occurs in the young, no reasons can be adduced for changing the name.Google Scholar

page 274 note 1 On this occasion it may be well to observe that Rütimeyer's statement, made with due reserve, but since repeated by others as an admitted fact, that, in some recent Pleurodira, the ischium anchyloses with the plastron before the pubis, was derived from the examination of figures accompanying one of Gray's memoirs; and that an investigation of the actual specimens which gave rise to this statement has proved it to be erroneous.—[G. A. B.]

page 274 note 2 = Acichelys = Aplax = Palœomedusa = Achelonia = Euryaspis = Parachelys.

page 274 note 3 Bull. Mus. R. Hist. Nat. Belg. vol. iv. p. 96 (1886).Google Scholar

page 274 note 4 The suggestion made in the above-quoted notice in the GEOLOGICAL MAGAZINE that the genus might perhaps be referred to the Trionychidœ will not hold.—[R. L.[

page 274 note 5 Reptilia of the London Clay, pt. i. pi. xxiii.

page 274 note 6 Rep. Brit. Assoc. for 1841, pp. 163 (1842).Google Scholar

page 275 note 1 Verh. Nat. Ges. Basel, p. 121.Google Scholar

page 275 note 2 Op. cit. pl. xxii.

page 275 note 3 Reptilia of London Clay, Supplement, pls. xxviii. A, B.

page 275 note 4 Ibid. pl. xxviii.

page 275 note 5 Verh. Nat. Ges. Basle, op. cit. p. 121.Google Scholar

page 275 note 6 Owen and Bell, Reptilia of the London Clay, pt. i. pls. xxv. xxvi.

page 275 note 7 These species will he described in a forthcoming memoir in the “Palæontologia Indica,” ser. 10, vol. iv. pt. 3.—[R. L.]Google Scholar