INTERNAL ANATOMY. 101 



ovaries, the receptaculum seminis, and the small tubes 

 joining the two last-named organs, they form a com- 

 plete ring ; which does not, however, retain a circular 

 form, or indeed any definite form; but being highly 

 flexible is, as far as I have been able to judge from the 

 species I have investigated, bent and doubled in any 

 direction so as to pack in between the other organs ; 

 and is not necessarily similarly arranged on the two 

 sides of the body. ISTalepa, however, as stated below, 

 was of opinion that he traced a definite plan in the 

 convolutions of the organ in T. loiujior. The tubes are 

 of very small diameter in the virgin female, and at that 

 period the cellulation of the walls may be distinctly 

 seen ; but they are highly elastic, and when the eggs 

 enter them they stretch to five or six times their 

 original diameter, or even more ; forming chambers 

 in which the eggs lie; or rather each egg forms a 

 separate chamber for itself by stretching the portion 

 of the oviduct in which it lies for the moment ; this 

 chamber in fact travels with the egg ; the oviduct 

 expanding as the egg is pushed on, and closing behind 

 it ; but it does not return to quite the small diameter 

 which it possessed in the virgin female ; in the process 

 it seems to lose all trace of cellulation, and becomes a 

 membrane in which little if any structure can be traced. 

 The chambers are not numerous because there are not 

 many eggs in an oviduct at one time, from two to six 

 being about the usual number in each oviduct when 

 the reproductive organs are in full action. The eggs 

 become longer and more elliptical in the oviduct ; their 

 sides being straightish the form is often almost that of 

 a cylinder with hemispherical ends. The eggs increase 

 in size in the oviducts from yolk- division, etc., and in 

 its distal part they receive their final exterior coat; 

 which is secreted by the epithelium of the oviduct. 

 This exterior coating is not a hard chitinized shell, as 

 in the Oribatidse, but usually a white and more or less 

 soft coat ; the oviducts themselves however greatly 

 resemble those of the Oribatidge, but they do not ter- 



