VI 



PROTRACHEATA 



433 



separating again and winding about the intestine, they run first for- 

 wards then outwards, and finally backwards towards the median line, 

 where they reunite to form the unpaired vagina, whose outer aperture 

 lies ventrally between the penultimate pair of legs. Each uterus 

 has in the part nearest the ovaries two appendages, a reeeptaeulum 

 seminis and reeeptaeulum ovorum. The former is a sac opening into 

 the uterus by means of two canals which unite at their mouths. 



This peculiar method of junction of the reeeptaeulum seminis and 

 the uterus is explained by ontogeny. The reeeptaeulum is originally 



FIG. 295. Female sexual organs of 

 an older embryo of Peripatus Edwardsii 

 (after Gaffron). U, Ovarial ligament; ov, 

 ovarium ; ro, funnel portion of the reeepta- 

 eulum ovorum ; rs, reeeptaeulum seminis ; 

 :it, uterus; va, vagina. 



FIG. i".n;. Male genital 

 apparatus of an adult Peri- 

 patus Edwardsii spivail out 

 (after Gaffron). t, Testis; 

 cs, vesicula seminalis ; ?, vas 

 ilrfcrcns ; de, cluctus ejacu- 

 latorius. 



only a U-shaped loop of the uterus. The two limbs of the loops unite 

 at a later stage (Fig. 295, rs), fuse together at their ends, and open 

 into each other, the partition wall disappearing. The limbs of the 

 U-shaped bend thus become the two connecting canals, and the median 

 piece (the bend of the U) becomes the sac of the reeeptaeulum seminis. 

 The reeeptaeulum ovorum, which enters the part of the uterus lying 

 between the ovary and reeeptaeulum seminis, consists of a funnel, 

 which enlarges at its free edge into a blindly-closed sac of connective 

 tissue filled with fertilised eggs. 



Peripatus is viviparous. The eggs develop in the uterus, in which all stages of 

 VOL. I 2 F 



