1668 Journal of Applied Microscopy 



GENERAL PHYSIOLOGY. 



RAYMOND PEARL, University of Michigan. 



Books and Papers for Review should be Sent to Raymond Pearl, Zoological Laboratory, 

 University of Michigan, Ann Arbor, Mich. 



Parker, G. H. and Arkin, L The Directive In- ^ statistical study of the direction of 



fluence of Light on the Earthworm Allolo- the movements of the anterior end of 



bophora foetida (Sav.), Amer. Jour. Physiol. , , a,i , , ,i 



4. j,,_j(._ jQQj ^ the common earthworm, AUolobophflra 



fxtida, when the organism is unilat- 

 erally stimulated by light, shows that (a) this form is negatively phototactic, 

 and (b) the intensity of the directive influence depends on the part of the body 

 stimulated. The directive influence was measured by the percentage of head 

 movements away from the light, as compared with those towards the light or 

 indifferent, after deducting the number of cases of turning away due to other 

 stimuli than light. When the whole length of the worm was illuminated on one 

 side, 26 per cent, of the head movements were away from the light; 10.2 per 

 cent, of the movements were away when the anterior third of the body only was 

 illuminated, and 1 per cent, when only the posterior third was illuminated. 



R. P. 



Godelmann, R. Beitrage zur Kenntniss von The author has made a very thorough 



Bacillus Rossii Fabr mit besonderer Beriick- g^^^j ^f ^^e interesting process of autO- 

 sichtigung der bei mm vorkommenden Au- ■' ° ^ 



totomie und Regeneration einzelner died- tomy Or self-amputation of limbs, and 



massen. Aixh f. Entvvickelungsmech. 12: -^^ connection with this the regenera- 



265-301, Taf. VI, 1901. ° 



tion in Bacillus Rossii, a representative 

 of the peculiar group of orthopterous insects, the Phasmidas. To test the 

 organism's power of regeneration after injury, parts of the legs and the abdom- 

 inal segments were removed by operation. It was found that the regeneration 

 was in general more complete the farther distal the cuts were made. In case 

 of the limbs no direct regeneration was observed following cuts made proximal 

 to the tibia. Instead, autotomy ensued and this was followed by regeneration. 

 In no case after operation were more than four tarsal joints regenerated, 

 while the normal number is five. The different pairs of legs showed differing 

 degrees of regenerative power. The most complete direct regeneration was 

 found in the middle pair, less complete in the anterior pair, while in the 

 posterior pair no direct regeneration following injury was observed, any injury 

 causing instead autotomy. Regeneration of a part of the last abdominal 

 segment was observed in one case. The regeneration of the legs after autotomy 

 was more complete than that following injury. Here in several cases a com- 

 plete pentamerous tarsus was regenerated. 



Autotomy always occurs at the point of junction of tlie trochanter with the 

 femur. Across the leg at this point is developed a diaphragm consisting of 

 loosely arranged, spindle-shaped cells evidently derived from the hypodermis. 

 The muscles of the femur have their origin just below this diaphragm in the 



