34 



00'3 



ME. J. S. BUDGETT ON THE STRUCTURE 



111 LejmJosteus, Balfour and Parker ^ found that the liollow ovary wa? formed by the 

 ventral edge of the ovary growing round and fusing mth the peritoneum, thus including 

 a portion of the body-cavity. Into this cavity in the larval Lepidosteus they found 

 nephrostomes opening; but Balfour says that he could not observe how the hind ends of 

 the oviducts were formed, but admitted that if there should be found nephrostomes 

 opening into this jiortitra of the duct, it would prove that the oviducts of LrpiiJostetis 

 are not true Miillerian ducts. Now this is precisely what we have in Tohjpterus. 

 Jungcrsen - has shown that the ovary of many Teleosteans is formed by the inclusion 



Text-fig. 5. 



LARVAL 9 



LARVAL 9 



LARVAL d 



LARVAL d" 



ADULT 9 



ADULT 9 



ADULT cf 



ADULT o' 



POLYPTERUS 



LEPIDOSTEUS 



POLYPTERUS 



LEPIDOSTEUS 



Scries of diagrams illustrating the suggested homologies of the genital ducts and vasa efFerentia in 



Poh/ptertis and Lepidosteus. 

 luyh., uephrostome of tubule passing to glomerulus; m.cps., glomerulus ; g.gr., thickened strip of peritoneum 

 or genital groove ; ^.r., genital ridge ; s.d., segmental duct; t.d., testis duct ; t., testis ; ov., ovary ; 

 v.ef., vas cfFerens ; ov.d., oviduct. 

 The dotted line in 3, 4, and 7 indicates that the nephrostomes no longer persist. 5 and 6 indicate a condition 

 believed to exist, but not yet proved. 



of a portion of the body-cavity much as Balfour and Parker described the process in 

 Lepidosteus, but, so far as I am aware, no one has found nephrostomes opening into the 

 ducts of the ovary. It seems fairly certain, then, that in the female Fohjpfcrus the 

 genital duct is not a Miillerian duct, that is, is not developed from the segmental duct. 

 In a previous paper ^ I described the genital duct in the male Pohjpterus, and gave 

 reasons for regarding the genital ducts in the male and female as homologous structures, 

 showing that in young specimens 9 cm. in length the hinder ends of the ducts in the 



' Loc. cit. 



' Trans. Zool. Soc. Lend. vol. xv. p. 323. 



Arb. Inst. Wiirzburg, Bd. is. 1889. 



