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area of the ovary, and are of varying sizes and arranged in regular rows ; 

 the ventral portion consists almost entirely of the delicate membrane 

 and has no germ cells. 



Each end of the ovary becomes continuous with a long coiled tube, 

 the oviduct, which passes forwards and upwards to form one or more 



loops, and ends by uniting with its fellow of the 



j r i ri ,1 Oviduct, uterus and 



opposite side to form a large sac-like organ, the uterus ; vagina 



at the point where the oviduct joins the ovary the 

 former consists of a delicate membrane and is easily torn. The oviduct 

 is lined by columnar cells which have large basally placed nuclei ; exter- 

 nal to the cellular layer there are some delicate muscular fibres which 

 are strongly developed in the impregnated female. The oviduct has 

 several dilated portions, very conspicuous in O. savignyi, the nature of 

 which is not clearly understood. The uterus, which is also spoken of 

 as the spermatheca, is a bicornuate organ formed by the junction of the 

 two oviducts ; it lies in the middle line below the mid-intestine. Its 

 structure is very similar to that of the oviduct, and in the unimpregnated 

 condition the circular muscle fibres surrounding it are not well developed. 

 At its anterior end it becomes continuous with the vagina, a short tube 

 which for purposes of description may be considered in three parts. 

 The first part extends up to the entry of the vaginal glands ; this 

 portion is lined by flat cells covered by a delicate epithelial intima, and 

 the muscles surrounding it are poorly developed in the unimpregnated 

 condition. The vaginal or accessory glands are long sausage-shaped 

 organs which open on each side of the first part of the vagina ; they are 

 similar in structure to the mucus accessory glands of insects. The 

 glands are not present in O. savignyi, but are well developed in Argas 

 Persicus and in the Ixodini. The second part of the vagina is short, and 

 has numerous papillae on its internal surface ; even in the unimpregnated 

 condition it is surrounded by a thick layer of circular muscle fibres. 

 Inserted into its external walls on each side there are strong bands of 

 muscles which arise from the dorsal integument ; these draw it towards 

 the dorsal surface. The third part of the vagina is usually named the 

 vestibule ; it leads directly to the external genital opening and is in close 

 contact with the ventral surface of the brain. In structure it is very 

 similar to the second portion, but the chitinous intima is better developed. 

 In the impregnated condition the ovary is seen to be increased in size 

 and to contain eggs at all stages of development ; these soon begin to 

 project from the surface and are easily dislodged. When the egg 

 attains maturity it is attached by a funnel-shaped neck, the junicle, 



