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Show 1886.] PROF. F. J. B E L L O N BIPALIUM K E W E N S E . 167 assigned to the genus Bipalium l. The only writer who seems to have remarked the variability in the form of the head is M . Humbert, who figures2 the head of Bipalium dianat as living and when it is greatly contracted ; the differences are, however, quite slight as compared with those in the figures now given (Plate X V I I L ) . Moreover, M . Humbert continues to use the form of the head as a distinctive character, and seems to have only incompletely appreciated the moral of what he saw. Referring to the paper of Prof. Perceval Wright, M . Humbert says:-" II donne une figure .... qui represente l'extremite' anterieure semilunaire et a du evidemment etre faite d'apres un individu conserve dans I'alcool, tandis que celle de la D. grayia a ete dessinee d'apres le vivant. C'est sans doute a ces deux manieres d'observer, encore plus qu'a des particularites specifiques qu'il faut attribuer les differences profondes que Ton remarque dans la forme des extremites anterieures de ces deux especes." But the differences shown in Prof. Wright's woodcuts of the two species are not as " profound" as those seen in the figures of the single living specimen here reproduced. So that, though M . Humbert recognized the difference between living heads and heads preserved in spirit, he does not seem to have recognized what is much more important-that the form of the head varies constantly during life. If a Planarian in a torpid condition (PI. XVIII. fig. I) be then and there seized and put into spirit, it will be found, no doubt, to have an obtusely blunted head, hardly wider than the body3; on the other hand, some, at any rate, if killed while in full activity, will be found to have heads shaped like a cheese-cutter or some modification thereof. Hab. Mr. Salvin has lately received orchids from S. America and S. Mexico, and from Burmah ; but he has also had specimens from Kew Gardens, whence the originals came to M r . Moseley. In 1883 Dr. Giinther received some specimens from Welbeck Abbey4, where they had been known for three or four years previously ; M r. Thiselton Dyer tells m e that there is no history of any communication between the gardens at that place and Kew, and adds " we have probably therefore been stocked from a common source." A specimen found in a greenhouse in Clapham Park was sent to Dr. W . M . Ord, and is now in the possession of Prof. Ray Lankester ; the early history of this specimen is unknown. In the hope of being able to extend our knowledge of this worm, I have written a note to the editor of the ' Gardener's Chronicle '5, which may result in some further information, and perhaps in the discovery of fresh examples 1 The French translator of the latest authoritative work on General Zoology by converting'' Kopftheil durch Lappen-Vorsatze halbmondformig " into'' Eegion cephalique en croissant par la presence de deux appendices lobes," shows that he too regards the lateral parts of the head as being constant in form and position; nevertheless they are not so. 2 Mem. Soc. Geneve, xvi. p. 303, figs. 1, 1 a. 3 Fig. H in Plate XVIII. shows the form of the head in the specimen under description, now that it is dead and preserved in spirit. 4 See his letter in the • Gardener's Chronicle,' xix. (1883) p. 415. 5 Published on March 13th, 1886. |