Miscellanvoua. 69 



before they open into the vesicula seminalis, lo^se their typical 

 eiiithclium and form 



7. The special glandular portion, which servos to secrete the 

 chitinous substance for the membrane of the sperraatophoref; ; 



8. The semen enters the sexual organs of the female in the form 

 of oval and somewhat flattened spermatophores. 



The female sexual organs are constructed in the following 

 manner : — 



1. The external genital aperture has the same appearance as in 

 the male ; 



2. The vagina is clothed with a thick chitinized iutima ; 



3. The receptacula seminis are represented by two vesicles with 

 chitinized intima, and open into the vagina in the neighbouihood of 

 the genital aperture ; 



4. On its posterior wall the uterus is provided with two auricu- 

 late appendages, which do not differ in histological structure from 

 the remaining portions of the uterus, and, as it appears, play no 

 physiological part whatever ; 



5. The oviducts pass immediately into the ovaries. The walls of 

 these two sections are longitudinally folded, in consequence of which 

 when the sexual organs become tilled with ova or spermatophores 

 they are capable of considerable expansion, whereby the cavity of 

 the organs is increased ; they consist of («) the external adipose 

 laj^er, {h) the circular musculature, (c) the longitudinal musculature, 

 (d) the tunica propria, and {e) the columnar epithelium. In the 

 first three layers an abundant ramification of tracheae is observable; 



6. The ova develop from a special epithelial layer, which clothes 

 the wall of the ovaries on the interior ; 



7. The ripe ova, which already lie in the follicles which become 

 evaginated, have a so-called " stylum " * ; 



8. In the cavity of the ovaries and of the oviducts there may be 

 observed a considerable number of free cells which bear a strong 

 resemblance to the blood-corpuscles. The cells possess the power 

 of amoeboid movement and exhibit figures of karyokinetic division. 

 They demolish the envelopes of the spermatophores, thereby libera- 

 ting the spermatozoa, and at the same time destroy the superfluous 

 spermatozoa and the unfertilized ova f ; 



9. The ripe ova fall into the cavity of the ovaries, where the 

 development of the embryo is completed ; 



10. Even before the formation of the rudiments of the appen- 

 dages a great difference in form is noticeable between the thoracic 



* Bertliau, '' Uebor den Generationsapparat der Araueiden," Archiv f. 

 Natu^ge^^chichte, 1875, p. 245. 



t Corpuscles of this kind have been described by Prof. A. Schneider in 

 Nephelis, Aulostomum, and Hirudo—A. Schneider, " Ueber die Audosiing 

 der Eier inid Spermatozoen in den Geschlechtsorganen," Zool. Anz. 1880, 

 no. 4(), p. 19. 



