THE ANATOMY OF POLYPTERUS. 525 
however, are smaller as compared with the testis-duct in the young than in the adult. 
It is noteworthy also that the vas deferens, which in the young is very thick-walled and 
has a larger lumen, is much larger as compared with the ureter in the young than in 
the mature individual (Pl. LI. figs. 14, 18, v.d.). 
In the young Polypterus the duct of the testis runs forward a short distance 
anteriorly to the testis. This portion of the duct could not be traced with certainty in 
the adult. No opening in the young male was found, however, into the body-cavity. 
In the very young male, 9 cm. in length, the tubules of the testis are foreshadowed 
by the nuclei being arranged in double rows, but there are no lumina; the duct, 
however, has a wide lumen and is well formed (PI. LIL. fig. 19, ¢.d.). At this stage the 
tubules of the testis-ridge are not yet developed ; the duct, however, is here well formed, 
as opposite the testis. Posteriorly the vasa deferentia end blindly in the wall of the 
ureter (Pl. LIL. fig. 20, w.v.u.). 
Ill. The Female Organs. 
The following observations have been made on adult female specimens of 
P. senegalus and P. lapradei taken at all times of the year, and also upon specimens 
of the young female P. senegalus 9 cm. in length. 
The funnel-like opening of the oviducts into the body-cavity (Pl. L. fig. 1, p.ap.od.) 
were mentioned and figured by Joh. Miiller; the ducts were figured in more detail by 
Hyrtl, and the ovaries were described. My own observations, however, do not in some 
respects agree with those of the latter author. According to Hyrtl the two oviducts 
unite to form a urinogenital sinus, into which the two ureters open by a common mid- 
dorsal aperture. 
I have carefully studied the adults of both species found in the Gambia, and I find 
that the ureters are dilated posteriorly, lying closely approximated to each other, but 
not communicating, except immediately before opening to the exterior (PI. L. figs. 1, 
4,u.; fig. 4, s.v.g.s.). Shortly before the ureters open to the exterior the oviducts open 
into their lateral walls precisely as do the vasa deferentia in the male (PL. L. fig. 4, g.ap.). 
Further, in the young female 9 cm. in length the course of these ducts has exactly the 
same relation to the ureter as in the male, only that the oviducts are considerably more 
dilated; they lie immediately over the genital ridge, which anteriorly is developed 
into the ovary (PI. LII. figs. 21, 22, 23, mes.o.). 
The great difference between the sets of organs in the male and female is that in 
the male the genital gland discharges directly into the duct, whereas in the female 
the genital products are shed free into the body-cavity, and thence find their way to 
the mouth of the duct. Were the outer wall of the duct in the female carried 
forwards to enclose that side of the ovary from which the ova are shed, or were the 
testis-duct in the male open anteriorly to receive the products of the testis from the 
body-cavity, the arrangement would be precisely analogous in the male and female. 
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