380 W. H. TALIAFERRO 



after self -amputation than clotting." The same author (29) 

 continues his work on the self-amputation of appendages in a 

 number of decapod Crustacea by making a comparative experi- 

 mental study of the reflexes, etc., involved in this act. 



Pearse (30) gives some interesting facts concerning the habits, 

 courtship, copulation, etc., of the fiddler crabs Uca pugnax and 

 U . pugilator. 



Pecker (31) has made an extensive study of the modification 

 of Colpoda and its cysts under the action of blood serum. 



Phipps (32) finds that several species of amphipods with which 

 he worked are negative both with reference to light intensity 

 and direction of rays, the latter being the more efficient as a 

 stimulus. The sign of the reaction can be reversed in most 

 cases by treatment with certain depressing agents, which effect 

 seems to be due to changes in certain metabolic processes. 



According to Polimanti (33) weak mechanical stimulation 

 with a glass rod causes Planaria to lengthen and show flight 

 movements while strong mechanical stimulation is followed by 

 complete immobility. From this the author holds that a weak 

 stimulus causes an excitation in the tonus of the animal while 

 a strong stimulus causes inhibition. He also concludes that the 

 mechanism of inhibition in its last analysis is one of fatigue. 



In a study of the function and structure of the grasping organ 

 of Dendrocoelum lacteum, Redfield (34) finds that this organ 

 ' is used to seize and hold material on which D. lacteum feeds. 

 It is stimulated to activity by appropriate materials applied 

 to the receptors located on the anterior part of the worm." 

 These receptors probably are on the grasping organ itself. The 

 organ may be used in some forms of locomotion but this cer- 

 tainly is not one of its essential functions. 



Root (35) gives an account of the life history and the reactions 

 to food of the su dorian Podopkyra collini n. sp. 



Schwartz and Safir (36) find that when the fiddler crab is 

 placed in a wooden box it tries to escape by moving persistently 

 toward some definite corner. The direction of this movement 

 is conditioned to a large extent by the comparative symmetry 

 of the two chelipeds, the dextrous males going to the right, etc. 

 If the corner to which a given specimen moves is closed by a 

 glass plate the animal will learn to go in some other direction 

 which offers the possibility of escape. The rapidity of this habit 



