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THE AMERICAN NATURALIST. [Vol. XXXVII. 



the walls of the dorsal vessel. In fixing these masses of egg 

 tubes it is advisable to tease them apart, otherwise the fixing 

 fluids may not penetrate to the interior of the masses or the 

 tubes may be difficult to isolate afterwards. Almost any modern 

 fixing fluid will give good results, though I have had most suc- 

 cess with picro-acetic (Boveri), picro-sulphuric (Kleinenberg) 

 and Zenker's fluid. After hardening in alcohol the ovarial tribes 

 may be stained from five to ten minutes in picro-hasmatoxylin 1 

 and then mounted entire ; such tribes show beautifully not only 

 the follicle cells in various stages of division but also the egg 

 cells in different stages of growth. However, for the accurate 

 study of the amitosis it is necessary to remov e portions of the 

 follicle by means of needles ; this can readily be done after the 

 tubes have been stained and dehydrated and while they are in 

 the clearing fluid. These pieces of the follicle can then be 

 mounted in balsam and. if desirable, can be studied under an 

 immersion lens, though the nuclei are so large that all the 

 details of the division can be made out with a magnification of 

 from 125 to 300 diameters. It is advisable to double stain those 

 tubes from which the epithelium is to be stripped, in picro- 

 hsematoxylin followed by a weak solution of eosin, or with acid 

 fuchsin and methyl green (Auerbach's formula) in order to bring 

 out the sharp contrast between the chromatin and the nucleoli. 



Each ovarial tube of the cricket consists of a number of sec- 

 tions, all of which except the first contain ova in various stages 

 of growth. These sections are, Fig. 1, (/) the terminal filament, 

 a thread of considerable length but of small diameter which 

 serves to attach the tube to the walls of the dorsal vessel ; (2) 

 an enlarged section, the terminal chamber, which contains ovo- 

 gonia and young ovocytes which are not arranged in a linear 

 series ; (J) a varying number of small ovocytes or eggs which 

 are arranged in linear series but are not completely separated 

 from one another by constrictions of the tube ; (4) a section in 

 which the egg eells are separated by deep constrictions, the epi- 

 thelial cells growing all the way through the tube and thus form- 



