Supplement to the fifth edition of A manual of elementary geology / by Charles Lyell.

  • Charles Lyell
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Supplement to the fifth edition of A manual of elementary geology / by Charles Lyell. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    family. The character of the calvarium of Triconodon offers no- thing adverse to the above views. * Besides the mammalia above alluded to belonging to 9 or 10 species and to 5 or 6 genera, all of them insectivorous or predaceous, we are indebted to Mr. Beckles for having disentombed (January 31. 1857) the remains of another genus exceedingly unlike the rest, the Fig. 1. Plagiaulax Decklesii, Falc. These two figures represent the same right ramus of the lower jaw seen on the opposite surfaces of a split stone, the two taken together affording d.ita for a complete restoration of the jaw. Upper figure (outer side). a,b,e'. Right ramus of lower jaw magnified two diameters, a, b, outer side, b, o\ d', e1, im- pression of inner side. a. Incisor. 6, c. Line of vertical fracture behind the pre-molars. rf'. Impression of the condyle in the matrix. e'. Impression of top of coronoid process. /. Section of the anterior piece of ihe jaw at the fracture b, c,—x, inner surface; y, outer. The notcli at the top is formed by one of the sockets of the double-fanged true molar. g. Section of the hinder piece near b, c ; x, inner ; y, outer surface, o'. Broken off inflected fold of inner margin buried in the matrix. m. Sockets of two molars. p, m. Three pre-molars, the third and last divided by a crack. Lower figure (inner side). a',d. Same lower jaw on the opposite slab of stone; b,d,e, inner side; 6, a', h, cast and impression of outer side. a'. Outline of the incisor restored. 4, c. Line of vertical fracture, rf. Condyle. e. Coronoid. h. Impression on the matrix of the three pre-molars. i. Empty sockets of the two true molars. n. Orifice of dentary canal. o. Indication of the raised and inflected fold of the posterior inner margin. *. Third or largest pre-molar, magnified 5} diameters, showing the 7 diagonal grooves. /. Corresponding pre-molar in the recent Australian Hypsiprymnus Gaimardi, showing the 7 vertical grooves, magnified 3} diameters. * Allusion is here made to the crown of the skull before-mentioned as occur- ring in the same slab. In the text at p. 296., I have cited the opinion given by Professor Owen in 1854 (see Geol. Quart. Journ. vol. x. p. 431.), that the Spalacotherium was more nearly allied to the placental than to the marsupial insectivora, an opinion which, as will bo seen, he is now disposed to modify.
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