112 
ME. H. 1ST. MOSELEY ON THE ANATOMY AND 
Planarians alive in confinement failed. I never preserved them for more than a few days. 
Mr. Thwaites, who has also tried the experiment several times, has had a like result. 
Mr. Darwin seems to have found no difficulty in keeping Geoplance alive: he kept 
some alive in a box twenty-one days, and they increased in size during that time. 
The Planarians which I obtained were almost all procured in a Manilla-hemp plan- 
tation in the Royal Botanic Gardens, Peradeniya, Ceylon, under fallen leaves and under 
the leaf-sheathes of the growing plants. I found some in these situations myself ; but 
the larger number were procured by one of Mr. Thwaites’s coolies, trained by him as a 
collector. The coolie’s plan was to lay a large fresh plantain-leaf on the grass near the 
plantation, and in a few hours he found the Planarians adhering to the under surface. 
Three species of Bipalimn and one of Rliynchodemus were obtained all together in this 
manner. Occurring with the Planarians is found, as remarked by M. Humbekt {Log. cit. 
pp. 302-3), the mollusk Vaginulus , which was also found associated with Geoplana in 
South America by Mr. Darwin ( loc . cit. p. 241). Mr. Darwin was led to believe that 
Geoplana fed on rotten wood ; but this is most probably not the case. All Planarians 
appear to be carnivorous, like their congeners the Nemertines (MTntosh, loc. cit. p. 338) ; 
and it is possible that the increase in size observed in his specimens by Mr. Darwin was 
due to cannibalism on their part. Max Schultze searched carefully in the digestive 
tract of Geoplana (Halle Abhandl. loc. cit.) and found no trace of vegetable tissue in it ; 
but he did find the palate and jaws of a snail. 
Fr. Muller (Halle Abhandl. loc. cit. p. 27) says that Geobia sucks out the juices of its 
host Lumbricus corethrurus. Leidy (Proc. Acad. Sci. Phil. 1858, p. 172) fed Bhyncho- 
demus sylvaticus with crushed house-flies ; and although I have examined microscopically 
sections of twenty or thirty individuals of four species of Ceylon Land-Planarians, I have 
never seen a trace of vegetable tissue in their intestines. As far as regards aquatic 
Planarians, Yon Baer, who was the first to give an account of the anatomy of Plana- 
rians and separate them from the Leeches, with which they had been confounded by 
Shaw and Kirby long ago, remarked (Nova Acta, tom. xiii.) on the carnivorous propen- 
sities of these animals ; and on Professor Rolleston placing an earthworm, killed by 
immersion in warm water, in a dish in which were a number of living Planarice torvce 
and Dendroccela lactea , these animals crowded on to the worm’s body and soon sucked 
all the hsemoglobin out of it, leaving it white and pulpy. 
Dr. Leidy remarked that from the tail end of Rliynchodemus sylvaticus is secreted a 
delicate mucous thread ; and Sir J. Dalyell (loc. cit. vol. ii. p. 113) observed of Planaria 
Arethusa that it makes threads of mucus, by means of which it suspends itself in the 
water. Bipalium in the same manner uses a thread of its tough investing slime for 
suspension in air ; and I have frequently seen it let itself down in this manner from a 
twig held at a short distance from the ground. The cellar-slug makes use of a slime- 
thread for suspension in the same manner. This fact in the habits of Bipalium does 
not seem to have been noticed by M. Humbert, although he gives a very interesting 
account of that animal’s mode of life in his memoir (Mem. Soc. Phys. de Geneve, xvi. 
