IU4 jM. E. Bordage on the Spiral Growth of Appendages XLIII. — On the Spiral Growth of Appendages in Course of Regeneration in Arthropoda. By Edmond Bordage *. T. — Tn a previous communication to tlie Academy I noted tlie spiral manner of g-rowth of limbs in process of regenera-tion among the Mantida\ I recalled the fact that this special mode of growth is common to the PiiasmidjB and to the Blattidte t-I should add that this peculiarity ought probably to be met with in the four classes of Arthropoda and in the case of different appendages |. So far as insects are con-cerned, the fact is now proved as regards the limbs. Further-more, 1 have been able to convince myself that after anij)Utation the antennae of the larvse of Pliasmidaj {Monan-droptera and Raphiderus) grow in a spiral until the first moult which follows the mutilation. Among the Crustacea spiral growth has been determined in Cancer paguriis, Corcinus 77?<TB?m.v, and Pagurus Bernhardus by II. Goodsir ('Anatomical and Pathological Observations,' Edinburgh, 1845). Among the Arachnida the Araneidea show it clearly. In j\lyriopoda it has not yet been noted. It seems probable, however, from what few researches have been made upon regeneration of limbs among these Arthropoda. It should most probably be seen at least in I\lyriopods with well-developed limbs, such as the Seutigera3 [Scutigera). The latter present a remarkable peculiarity. Before they have attained their full development there can be made out rolled up under the skin, owing to its transparency in the terminal segment of the body, a number of limbs — limbs which do not become free and rectilinear until the following moult. After each moult the body of Scutigera gains an additional segment. II. — I ought, however, to mention that spiral growth is not met with in all Arthropoda. In the lobster, for instance, the thoracic limbs when in process of regeneration grow in a rectilinear manner. This fact is the more remarkable inasmuch • Translated from ' Comptes Tlendus,' cxxix. (1899) pp. 455-457, by Wilfred Mark Webb, F.L.S. From a separate impression communicated by the Author. t I have just discovered that Mr. H. Brindley had noted this manner of gro\vth in the Blattidje (Brindley, ' On certain Characters of Repro-duced Appendages in Arthropoda/ p. 9, IS'.iS). :J: Researches, experimental as well as bibliographical, have, however, shown me that this mode of growth is not met with in all the Arthropods, as one would have been at tirst inclined to suppose.
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