BEHAVIOR OF LOWER INVERTEBRATES 377 



lower in the absence of such influence. The rhopalia likewise 

 seem to have some influence on certain metabolic activities. 



Child (9) by means of his " differential susceptibility to cyan- 

 ide " method and Lillie's indophenol method of determining 

 intracellular oxidations, finds that there is a metabolic gradient 

 in the unfertilized egg of the star fish which coincides in direction 

 with the axis determined by the excentric position of the nucleus. 

 This gradient disappears in the bipinnaria larvae as metamor- 

 phosis approaches. 



Crozier (10) finds that Holothuria surinamensis " is reactive 

 to tactile, vibratory, photic and chemical stimuli. It is practi- 

 cally indifferent in a sensory way, to heat." The following is 

 the order of decreasing sensitivity of parts of the animal: " ten- 

 tacles > anterior end > posterior end > papillae, pedicles (podia) > 

 mid-body surface." Also he (11) finds that the Cuvierian organs 

 of Holothuria captiva are expelled in response to mechanical 

 but not to various chemical stimuli. He then takes up the 

 mechanism of the discharge of these organs and the cause of 

 their adhesiveness after the discharge. In continuing his work 

 on the latter organism he (12) finds that it is sensitive to light 

 and shading over its entire surface and concludes that photic 

 orientation in this animal is in accord with Loeb's definition of 

 negative phototropism. The same author (13) gives a note 

 on the behavior of a species of Ptychodera and another (14) on 

 the rhythmic pulsation of the cloaca of Stichopus moebii. 



Garrey and Moore (15) have attempted an experimental 

 analysis of " the normal progressive movements of the earth- 

 worm " in regard to such things as the initiation of peristalsis, 

 role of ventral nerve, etc. 



Hirsch (16) has made a very careful study of the biology of 

 nutrition of carnivorous gastropods. The work is too extensive 

 to do more than call attention to the original article. 



Hutchison (17) finds that M/100 and M/50 NaCl, M/3000 

 CaCl 2 , M/50 KN0 3 and distilled water, by increasing the heat 

 resisting powers, exert a protective action on a pure race of 

 Paramoecium caudatum grown in an alkaline medium. On the 

 other hand M/4000 CaCl 2 , M/100 NaCl and distilled water 

 exert an adverse effect on a pure race grown in an acid medium. 

 The author is of the opinion that these " experiments seem to 

 point to the conclusion that certain properties of the medium 



