78 University of California Puhlications in Zoology. [Vol. 4 



moment. Fine floeeulent material is not seized at all unless the 

 pedicellariae are stirred up by stimulating them with a needle, 

 or the like, and it is held but a few seconds. Possibly pressure 

 on the internal surface of the jaws is necessary to cause the pedi- 

 cellariae to hold. Yet a tube foot from another starfish was held 

 tightly till it was broken off in pulling away. And small hard 

 objects are sometimes released a moment or two after seizure. 

 just as soft ones are. 



It is clear that the holding by the pedicellariae depends on 

 many factors, doubtless to a large degree internal, so that the 

 precise behavior of a given individual pedicellaria can not well 

 be predicted. 



(6) The large solitary pedicellariae are usually less inclined 

 to hold objects a long time. Usually they release in a few mo- 

 ments even hard objects, and notwithstanding the fact that they 

 stir or pull. But there is much variation in different pedi- 

 cellariae. Thus, two of these large pedicellariae were standing 

 near together on the same starfish. A small, soft insect larva 

 was dropped into the open jaws of one of these. It at once closed 

 on the larva, then opened again, and repeated this several times, 

 finally remaining open. Its neighbor was given a similar larva ; 

 it thereupon closed and held it tightly for two minutes, when the 

 larva managed to pull away. The leg of a large bloAv-fly was 

 placed between the jaws of the first of these two pedicellariae. 

 It was at once seized, then at once released, though the fly 

 struggled and pulled. Then the same leg was placed between 

 the jaws of the second pedicellaria. It at once closed and held 

 on stoutly for three hours and forty minutes, the fly struggling 

 and pulling for a long time. I then broke oft' the observation. 

 It is therefore evident that sometimes the large pedicellariae 

 may hold on indefinitely, though this is not so common as with 

 the small ones. 



In thus holding for long periods, the pedicellariae of this 

 starfish appear to differ from those of the sea urchins. Von 

 Uexkiill reports that the latter hold an object seized for only 

 about two minutes. 



Seizing parts of the Starfish. — In another way the pedi- 

 cellariae of the starfish differ from those of the sea urchin, as 



