THE ANNALS AND xMAGAZINE OF NATURAL HISTORY. [SIXTH SERIES.] No. 63. MARCH 1893. XXIX. — The Affinities and Origin of the Tardigrada. By Prof. J. von Kennel *. Like the majority of the so-called aberrant groups in the Animal Kingdom the Tardigrada have met with the most diversified experiences in systems of classification. At one time they were ranked among the *' Worms," at another among the Arthropods, and they have been assigned at diffe-rent periods both to Crustacea and Tracheata. They were treated as an " appendage " to these groups or else as " ancestors " of them, and were regarded as degenerate or greatly reduced or as highly primitive forms. A comparison of the various views upon this question has been furnished by Plate t, who also discusses in a subsequent paper \ a theory by Biitschli § which had previously escaped his notice. Now I am in entire agreement with Plate's view that the Tardigrada can be brought into relationship only with the tracheate Arthropods, and do not consider it necessary to support or amplify the arguments which he advances against * Translated from the ' Sitzungsbericlite der Naturforscher-Gesellschaft bei der Universitat Dorpat,' ix. Bd. Heftiii. (Dorpat, 1892), pp. 504-512. t Plate, " Zur Naturgeschichte der Tardigraden," Zool. .Tahrb. Bd. iii. X Plate, " Die Rotatorienfauna des bottnischen Meerbusens &c.," Zeitschr. f. wiss. Zool. Bd. xlix. § O. Biitschli, " Untersuchungen iiber freilebende Nematoden und die Gattung Chatonotus,'^ Zeitschr. f. wiss. Zool. Bd. xxvi. Ann. & Mag. N. Hist. Ser. 6. Vol. xi. 15
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