STRUCTURE AND DEVELOPMENT OF LEPIDOSTEUS. 813 



and the dehiscence of the ova into this cavity is equivalent to 

 their discharge into the body-cavity in other forms. 



The oviduct (Plate 39, fig. 60, od.} is a thin-walled duct of 

 about 21 centims. in length in the example we are describing, 

 continuous in front with the ovarian sack, and gradually tapering 

 behind, till it ends (od'.} by opening into the dilated terminal 

 section of the kidney duct on 'the inner side, a short distance 

 before the latter unites with its fellow. It is throughout closely 

 attached to the ureter and placed on its inner, and to some 

 extent on its ventral, aspect. The hindermost part of the oviduct 

 which runs beside the enlarged portion of the kidney duct 

 that portion called by Hyrtl the horn of the urinary bladder is 

 so completely enveloped by the wall of the horn of the urinary 

 bladder as to appear like a projection into the lumen of the 

 latter structure, and the somewhat peculiar appearance which 

 it presents in Hyrtl's figure is due to this fact. In our examples 

 the oviduct was provided with a simple opening into the kidney 

 duct, on a slight papilla ; the peculiar dilatations and processes 

 of the terminal parts of the oviduct, which have been described 

 by Hyrtl, not being present. 



The results we have arrived at with reference to the male 

 organs are very different indeed from those of our predecessor, 

 in that we find the testicular products to be carried off by a series 

 of vasa efferentia, which traverse the mesorchium, and are con- 

 tinuous with the uriniferous tubuli ; so that the semen passes 

 through the uriniferous tubuli into the kidney duct and so to the 

 exterior. We have moreover been unable to find in tJu male a duct 

 homologous with the oviduct of the female. 



This mode of transportation outwards of the semen has not 

 hitherto been known to occur in Ganoids, though found in all 

 Elasmobranchii, Amphibia, and Amniota. It is not, however, 

 impossible that it exists in other Ganoids, but has hitherto been 

 overlooked. 



Our male example of Lepidosteus was about 60 centims. in 

 length, and was no doubt mature. It was smaller than any 

 of our female examples, but this according to Garman (vide, 

 p. 361) is usual. The testes (Plate 39, fig. 58 A. A) occupied 

 a similar position to the ovaries, and were about 21 centims. 

 long. They were, as is frequently the case with piscine testes, 



