330 ME. J. S. BUDGETT ON SOME POINTS IN 



view which was latterly held by Balfour that primitively the testis had a duct of its 

 own, derived either from a Miillerian duct like that of the female Elasmobranch, 

 or a structure sui generis, as held by Howes and Max Weber, and that, on the other 

 hand, the connection of the testis with the tubules of the kidney found in the male 

 Elasmobranch, Amphibian, and Amniot is a secondary one. 



There is, however, a difficulty with regard to the latter view in the fact that 

 Lepidosteus, the Ganoid fish which, as regards its ovary and oviduct, most closely 

 resembles the Teleostean arrangement, in having a closed ovary continuous with its duct, 

 is the very one which shows this supposed secondary connection of testis with kidney. 



It is possible, however, that this acquirement is confined to Lepidosteus, while 

 other Ganoids retain the primitive condition ; and it may be that it is a feature which 

 has been frequently acquired independently. So that the Elasmobranch, Amphibian, 

 and Amniot are not necessarily a separate evolutionary line from the Crossopterygian, 

 Dipnoon, Ganoid, and Teleost, but the Amphibia may have acquired the Elasmobranch 

 arrangement after they split off from the Dipnoi, which have not acquired it. 



That the arrangement in Lepidosteus is not primitive seems probable from the fact 

 that the testis-tubules open into a well-marked longitudinal collecting-duct, which 

 lies along the ureter in the same position as the testis-duct in Polypterus, and it is 

 from this longitudinal duct that the transverse tubules pass to the kidney. 



That the arrangement in Polypterus is not secondary seems probable from the fact 

 that not only is it the simpler method of conveying the testis-products outwards, but 

 is, on the whole, closely similar to the arrangement in the female Polypterus, and we 

 can hardly suppose that in the primitive vertebrate the ova and spermatozoa found 

 exit by totally different means. 



VII. Abdominal Pores. 



In both male and female, abdominal pores are present in Polypterus. They have 

 been correctly described in the adult as fine canals opening to the exterior on either 

 side of the vent (PI. L. figs. 7, 8). In the young female 9 cm. in length there is a very 

 fine nucleated diaphragm cutting off the communication of the ccelom with the exterior. 

 This is, however, extremely delicate (PL L. fig. 9, ab.p.). 



In the young male 9 cm. in length the ccelom is completely shut off from the 

 exterior, the abdominal pores not being yet formed. 



VIII. The Anal Fin. 



Traquair has already noted in Calamoichthys that the males have an enlarged anal fin. 

 In Polypterus, during the breeding-season at least, this difference is not merely one of 

 size but also of shape and form, as shown in PL L., figs. 1 & 2. 



The anal fin in the female is narrow and pointed, while in the male it is twice as 

 deep as in the female, and its surface is thrown into deep folds between the successive 



