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III.—The Development of the Skull and Visceral Arches in Lepidosiren and Protopterus

Published online by Cambridge University Press:  06 July 2012

W. E. Agar
W. E. Agar
Affiliation:
Junior Demonstrator in Zoology atGlasgow University.
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Extract

The material for this work was that collected and prepared by Professor J. Graham Kerr in the Chaco (Lepidosiren), and by Budgett from the Gambia (Protopterus). The process of development follows nearly the same course in the two genera, and where differences occur they are mainly such as are to be expected from a comparison of the adult skulls. While the series of stages of Lepidosiren left no unfilled gaps, the material was scantier in the case of Protopterus. Except where otherwise stated, the detailed descriptions were worked out in Lepidosiren, but whenever I was unable to verify that the process was substantially the same in the other genus, the fact has been mentioned. The stages are numbered in correspondence with the stages figured by Graham Kerr (Phil. Trans. Roy. Soc, B., vol. cxcii.). The Protopterus stages are numbered the same as the corresponding ones in the other genus. As far as possible, the nomenclature adopted by Gaupp* has been adhered to.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 45 , Issue 1 , 1906 , pp. 49 - 64
Copyright
Copyright © Royal Society of Edinburgh 1906

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References

page 49 note * “Die Entwickelung des Kopfskeletes,” in 0. Hertwig's Handbuch.

page 49 note † Kerr, Graham, Quart. Journ. Micr. Sci., vol. xlvGoogle Scholar. part i.

page 51 note * Pinkus, , “Die Hirnnerven des Protopterus annectens,” Morph. Arb., Bd. iv. 1895Google Scholar.

page 51 note † Trans. Zool. Soc, 1898.

page 51 note § Beiträge zur Morphologie des Skeletes der Dipnoer, 1904.

page 51 note ‡ Anat Anz. Bd. xxi., 1902Google Scholar.

page 52 note * Quart. Journ. Micr. Set., vol. xlvi.

page 52 note † Phil. Trans. Roy. Soc, 1871.

page 53 note * Ueber die Spino-occipitalen Nerven der Selachien, etc., Fest.für Gegenbaur, 1897.

page 53 note † In Lepidosiren. In Protopterus I had no stage showing the process of this immigration.

page 54 note * Zeitschr. für wiss. Zool., 1880.

page 56 note * Morphol. Studien. Jena, 1880Google Scholar.

page 57 note * Proc. Zool. Soc. Lond. 1876.

page 57 note † Owing to the larger gaps between the successive stages of Protopterus available, I have been unable to prove the original independence of this cartilage in this genus.

page 58 note * Proc. Zool. Soc. Lond., 1876.

page 58 note † Trans. Zool. Soc. Lond., vol. xvi. part vii., 1902Google Scholar.

page 59 note * Cf. fig. 10.

page 59 note † Agar, , Anat. Anz., Bd. xxviii., 1906Google Scholar.

page 60 note * The cartilage is not absorbed, but squeezed out at each end of the bony sheath as this thickens.

page 61 note * It should, however, be mentioned that Wiedersheim (loc. cit.) found in a young Protopterus that the mesethmoid filled up the whole space between the ascending processes of the palato-pterygoids, i.e. was more extensive than in the adult. In my 7·5 cm. specimen the mesethmoid had the adult form of a narrow, backwardly projecting spine of the internasal septum.