INTERNAL ANATOMY. 99 



was the first to do so, but he apparently only saw it 

 through the cuticle of the abdomen ; he says * that it is 

 " une vesicule tres pale incolore de la partie posterieure 

 et dorsale du ventre." He does not appear to have 

 suspected that it was a receptaculum seminis. It seems 

 strange that an anatomist of Robin's excellence having 

 seen the receptaculum seminis and observed that the 

 posterior projection of Qlycyphagus was tubular, should 

 not have gone a step further and discovered the con- 

 nection of the two and their function. Of course 

 Nalepa fully recognised the nature of these organs, and 

 it is now, I believe, admitted by all acarologists. 



The Ovaries. PI. B, fig. 8, ov. 



These vary but little in the species which have been 

 investigated ; in Glycyphagus platygaster they consist of 

 two paired organs, roughly pyriform in shape, lying one 

 on each side of the receptaculum seminis; and each 

 joined to that organ by a short tube (ro). The ovarian 

 ova in various stages of development may be seen in 

 these ovaries, the largest and most developed being 

 usually found in the peripheral portions. The impreg- 

 nation of the egg takes place within the ovary. 



Nalepa gives the following account of the ovaries of 

 Tyrogiyphus longior ; he says that the ovaries lie one on 

 each side of the rectum near to the abdominal wall, and 

 that they are roundish but flattened on the side next 

 the rectum ; the oviducts commencing at the anterior 

 poles. He says that a section of the ovary shows that 

 it is formed like the testis ; the exterior tunic of eggs 

 in various stages surrounds a central nucleus-holding 

 plasmodic mass, the germ layer, the inner nuclei are 

 the smallest. The protoplasm surrounding a nucleus 

 separates itself off with the nucleus, forming an ovarian 

 egg without any yolk-membrane. The plasma is homo- 

 geneous, and scarcely stains with ammonia-carmine. 



* " Memoire zool. et anatom. sur divers especes d'Acaviens de la 

 famille des Savcoptides," I860, ' Mem. Soo. Nat. Moscou,' p. 292, pi. 

 viii, fig. 2. Jc. 



