AMITOSIS IN THE EGG FOLLICLE CELLS 

 OF THE CRICKET. 1 



EDWIN G. CON K LIN. 



That type of nuclear division known as amitosis or direct divi- 

 sion which was once supposed to be universal is now known to 

 occur so exceptionally that all teachers of cytology will welcome, 

 I think, the announcement of its existence in great beauty and 

 profusion in a common animal of wide distribution. It is this 

 consideration which leads me to publish the observations here 

 recorded which were first made more than six years ago. 



It has been long known that one of the most favorable objects 

 for the study of amitosis is to be found in the egg follicle cells 

 of certain insects (cf. Carnoy '85, Korschelt '86, Preusse 

 '95); in most .if not all of these cases, however, it occurs only 

 occasionally and must be searched for among many cells which 

 do not show it. However in the case of the common crickets, 



cell in the enlarged portion of the ovarial tubes shows some stage 

 or other in the process of direct nuclear division, and these cells 

 are so easily prepared and they show every step of the division 

 with such diagrammatic clearness that they cannot fail to become 

 favorite objects for class demonstration. 



A few words as to the structure of the ovarial tubes of the 

 cricket and as to the best methods of preparing them for the 

 demonstration of amitosis may not be out of place. If a mature 

 female cricket, which can readily be distinguished from the 

 male by the presence of the long median ovipositor, be torn in 

 two it will be seen that a large part of the abdomen is occupied 



either side of the body ; these tubes are attached behind to the 

 right and left oviducts and in front, by long slender filaments to 



1 From the Zoological Laboratory of the University of Pennsylvania. 

 667 



