536 EAVMOND I'EAKL. 



as quickly as any other louil. 1 luivo several times seen 

 specimens thus eaten. It is, in fact, possible, with a little 

 patience^ to make a specimen eat a small piece cut off tlie 

 posterior end of its own body ! This eating of each other 

 does not occur, so far as I have observed, unless an individual 

 is bruised so that some of the tissue underlying the epidermis 

 is exposed. Under these conditions juices escape from the 

 body and act as stimuli on the other worms. Under normal 

 conditions contact of one individual with another does not 

 start the feeding reaction, which is a purely reHex pheno- 

 menon, capable of being started only by a certain set of 

 stinmli. Promiscuous cannibalism, such as Child (:Ul) 

 suspects to occur among individuals of Stichostemma, 1 

 have seen no evidence for among the Turbellaria.^ 



In the feeding the worm lies fully distended, with the 

 posterioi- two thirds of the body on the meat^ or whatever 

 else is being used for food ; the pharynx is extruded, 

 frequently to nearly half the length of the body, audits end is 

 attached to the meat. During the feeding the very anterior 

 end of the Avorni is attached to the bottom of the dish, provided 

 the piece of food is not so large as to make this impossible. 



Besides the animal food which the worms will take so 

 I'eadily, they also normally, probably to some extent, feed on 

 vegetable matter, although I have not been able to induce 

 the typical food reactions (to be discussed later) with vege- 

 table material. The evidence for the statement that 

 vegetable food is used by planarians is of two sorts : [a) 

 specimens are frecjuently found extended on the stalks of 

 water ])lants, with the ]iharynx extruded and attached to the 

 stalks; and {J>} the fi,i3ces which have been observed immedi- 

 ately alter defecation have been found to consist largely of 

 liiiely divided jilant tissue, ft would apjiear, howevei", that 



' J5;irilccii l:01, A, ji. ]7(J) says, "SU-oiii,' |ilaiiariiiiis ol'lcii prey ii|kiii weak 

 ones. Til such instances the strong individual altaclies its [jliaiynx somcwlieie 

 u|)on tile body of tlie weak one, usually near Uic head." I liavo never seen 

 even the largest sjieeiiiieiis eat smaller ones unless lliese latter were bruised 

 in some way. 



