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Show 176 MR. F. FINN ON A FUNCTIONAL DUCTUS [Feb. 17, are three gizzards, which, like those of Heliodrilus and Hyperiodrilus, are situated at the junction of the intestine and oesophagus ; each gizzard occupies a single segment. These three genera, which belong to Perrier's Intraclitellian group, show that one of the characters made use of to distinguish that group from the Anteclitellians no longer holds. M . Perrier 1 writes :-" Chez les Lombriciens ante-clitelliens que nous avons etudie's, le gesier s'est toujours trouve place en arriere des organes gSnitaux et de leurs organes accessoires, en arriere aussi des anses contractiles ou cceurs lateraux del'appareil circulatoire. Dans ce3 Vers, l'cesophage est d'ailleurs tres-allonge et la ceinture rejetee relativement tres-loin en arriere ; quelquefois presque au milieu du corps. " A u contraire, chez tous les Lombriciens intra- ou postclitelliens, le gesier est place en avant des testicules et des ovaires, c'est-a-dire en avant des organes essentiels dela generation. II est egalement en avant des centres d'impulsion du sang, que ce soient des cceurs dorsaux impairs, comme chez YAnteus, ou des cceurs lateraux, comme chez les autres Lombriciens." Since Dr. Horst has discovered 2 an Intraclitellian earthworm, Glyphidrilus, in which the clitellum occupies the " anteclitellian " position, viz. from segment 23-31, it is impossible any longer to retain the group " Antecli-telliens." It is clear, from this brief account of the salient features in the structure of Libyodrilus, that it forms a quite new generic type, concerning the particular affinities of which I do not for the present offer any suggestion. 7. O n a Functional Ductus Botalli in Nycticorax violaceus and Dafila spinicauda. By F R A N K F I N N , B.A., late Scholar of Brasenose College, Oxford. (Communicated by F. E . B E D D A R D , F.Z.S., Prosector to the Society.) [Received February 17, 1891.] In his memoir on the " Development^ the Branchial Arches in Birds," published in the Transactions of the Royal Society of London for 1888, Dr. J. Mackay has described and figured an abnormality which he met with in the dissection of a Guillemot (Lomvia troile). This consisted in the existence of " the remains of the dorsal connection between the third and fourth arches upon the right side," " as a distinct cord passing between the common carotid artery and the descending portion of the aortic arch." Dr. Ferdinand Hochstetter also records two obliterated ductus botalli in Aquila ncevia and Circus cineraceus («« Ueber den Ursprung der Arteria subclavia der Vogel," Morph. Jahrb. xvi. p. 484, 1890). 1 "Memoires pour servir etc.," Nouv. Arch. Mus. t. viii p 156 Nederl. Dierk. Vereen. Verslag. op. d. Vergad. v., 26 Oct. 1889. |