1886.] PROF. F. J. BELL ON BIPALIXJM KEWENSE. 167 



assigned to the genus Bipalium \ The only writer who seems to 

 have remarked the variability in the form of the head is M. Hum- 

 bert, who figures" the head of Bipalium dianaa,s living and when 

 it is greatly contracted ; the diiferences are, however, quite slight as 

 compared with those iu the figures now given (Plate XVIII.). More- 

 over, 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 

 I'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 difi'erences profondes que Ton 

 reniarque 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, hardlywiderthan the body'; 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 Mr. Moseley. 



In 1883 Dr. Giinther received some specimens from Welbeck 

 Abbey*, where they had been known for three or four years pre- 

 viously ; Mr. Thiselton Dyer tells me 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 ' °, which may result in some 

 further information, and perhaps in the discovery of fresh examples 



^ The French translator of the latest authoritative work on General Zoology 

 by converting ' ' Kopftheil durch Lappen-Vorsatze halbmondformig " into ' ' Region 

 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. 



^ Mem. Soc. Geneve, xvi. p. 303, iigs. 1, 1 a. 



^ 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. 



* See his letter in the ' Gardener's Chronicle,' six. (1883) p. 415. 



' Published on March 13th, 1886. 



