DEVELOPMENT OF PARAVORTEX GEMELLIPARA 457 



Concerning the presence or absence of a bursa seminalis 

 Wahl says nothing, but his figures of the reproductive organs 

 show very clearly that no such reservoir exists in Paravortex. 

 We have already seen that this organ is characteristic of Graffilla. 



According to Wahl, the genus Paravortex is distinguished 

 from Graffilla, since its members have the genital pore situated 

 in front of the middle of the body while in Graffilla this open- 

 ing is at or behind the middle. The ovaries of Paravortex 

 are club-shaped, while those of Graffilla are sinuous and band- 

 shaped. The testes of Paravortex are nearly spherical; those 

 of Graffilla appear bottle-shaped. 



Von Graff gives ('08) a key to the Family Graffillidae, which 

 is translated in part below: 



A. With two germo-vitellaria and two compact, unlobed testes. 



1. Pharynx well developed, germo-vitellaria not lobed Vejdovskya 



2. Pharynx small, germo-vitellaria lobed in the form of a hand. .Paravortex 



B. With two ovaries and two vitellaria. 



1. Ovaries club-shaped, of normal size. 



a. Vitellaria long and unbranched. 



1. Testes paired, genital pore on ventral surface .... Paravortex 

 2 Testis single, genital pore at or near the posterior end 



CoUastoma 



b. Vitellaria branched (Testes paired, genital pore near posterior 



end) Umagilla 



2. Ovaries of different form, vitellaria branched or lobed. 



a. Ovaries abnoi'mally long cylindrical cords, vitellaria lobed in 



form of a hand, genital pore central Graffilla 



b. Ovaries and vitellaria hand-shaped, genital pore at the posterior 



end Syndesmis 



Thus it is seen that, according to von Graff, the genera Para- 

 vortex and Graffilla differ in that the former has two hand- 

 shaped germo-vitellaria, i.e., the ovary and the branched vitel- 

 larium of each side unite at their proximal ends to form a single 

 stalk which joins the oviduct. Graffilla, on the other hand, 

 has two extremely long cylindrical ovaries which are not thus 

 joined to the vitellaria; the latter, however, are branched. 



Von Graff in his key did not refer to the receptaculum seminis, 

 nor does he in the description of the genera dwell particularly 

 upon this point. Nevertheless, while he fails to mention the 

 organ in speaking of Paravortex, he notes that all the species 



