96 WORMS. [1900 



from behind the head, aud the head itself was of the bifid form figm'ed 

 at "6" ; but, whilst I had the specimen under observation, I did not 

 notice any alteration in the form of the head. 



One extraordinary characteristic of this species of " Flatworm " is 

 the power it possesses of altering the shape of the head. The fullest 

 observations of which I have knowledge are of those of Prof. F. Jeffrey 

 Bell, referred to below" ; and in these he particularly directs attention 

 to the variability of the form of the head, so that, whilst the " cheese- 

 cutter ■' or hammer-shaped heads (see figs. 1 and 5, p. 95) are very 

 commonly known forms, there may be other shapes — as knob-like, 

 tongue-like, or altogether irregular. Of these and other forms, Prof. 

 Bell gave a series of figures in the plate accompanying his paper, and 

 it seems to me to be of great interest that not only should there be a 

 difference in the shape of the head under different conditions, but that, 

 as personally observed by Prof. Bell, the head of a single specimen 

 should vary considerably and almost constantly in form, and it is from 

 the changes of one specimen that the figures given are represented. 



In regard to the specimen which came under my own observation, 

 which was forwarded to me in moss from a hothouse or some similar 

 locality, I saw nothing at first excepting a sort of slimy-looking streak. 

 By way of possibly rousing whatever the thing might be to a more 

 lively condition, I placed the moss in some very slightly warmed water, 

 and the effect was rapid. The creature became evidently alive, and 

 gathered itself together into the shape of what might be described as 

 a small snake with a bifid head, but much shorter than fig. 1. p. 95 ; 

 and, apparently not finding its quarters comfortable, set out almost 

 immediately on a journey up the sides of the bowl in which the 

 moss was placed, carrying its bifid head steadily before it, and by 

 means of its flattened under surface making very solid though slow 

 progress. 



Being then wholly unacquainted with the nature and habits of 

 what to my thinking was a very repulsive-looking creature, I fastened 

 it up again in its box, and, after gathering what information I could 

 about it, published this in my Annual Report for 1900, pp. 111-113. 

 At the time, this was little more than that this "Plauarian"' was 

 sometimes found (even for many years, if once established) in hot- 

 houses, and that it had a great power of secreting slime, so that minute 

 objects causing annoyance could be thrown off " in a continuous sheet 

 of mucus." 



* See " Note of Bipalium kewense and the generic characters of Land Plana- 

 rians," by Prof. F. Jeffrey Bell, M.A., Sec. K.M.S., in ' Proceedings ' of the Zoological 

 Society of London, 1886, pt. ii. pp. 166-168. Figures 1-5, at p. 95, are copied from 

 plat€ accompanying the above-mentioned " note,'' excepting that the position of 

 lig. 1 is altered to adapt it to space. 



