328 MB. J. 8. BUDGETT ON SOME POINTS IN 



will answer perfectly for that in Polypterus, except that in my youngest specimen 

 9 cm. in length I can find no trace of the nephrostomes opening into the coelom 

 described by him in "larvae" 12 cm. in length. It seems, then, that Calamoichthys, 

 which is so much smaller in the adult than Polypterus, is in a more larval condition 

 at 12 cm. length than is the Polypterus at 9 cm. 



It is possible that the nephrostomes never entirely close in Calamoichthys. However 

 this may be, I have found in Polypterus no trace of nephrostomes opening into the 

 coelom. 



In my youngest specimens the uriniferous tubules were arranged in distinct 

 metameric masses, the metamerism disappearing in older specimens. The glomeruli 

 did not appear to be thus arranged, there being a very indefinite number of these 

 structures to each metamere (PI. LI. figs. 10, 16, m.cps.). The openings of the tubules 

 into the ureter are far more numerous and irregular in the adult than in the young. 



V. The Ureters. 



The ureters lie along the whole length of the kidney between the outer ventral 

 edge of the latter and the body-wall (PI. L. figs. 2, 3 ; PI. LI. figs. 10, 11, %.) (text- 

 figs. 5, 6). They receive the kidney-ductules. The ureter on passing ventralwards 

 from the hind end of the kidney becomes dilated, and, in the male, joining its fellow of 

 the opposite side, forms a large urinary sinus (PI. L. figs. 2, 5, 6 ; PI. LI. fig. 12, u.s.). 

 The urinary sinus still passing ventralwards to a position just dorsal to the rectum 

 becomes constricted to a narrow neck and, just before opening to the exterior, receives 

 on either lateral wall the opening of the genital duct, then opens to the exterior in a 

 depression just posterior to the anus (PI. L. figs. 6, 7, 8, u.g.ap.). 



In the female the ureters do not become confluent until immediately before they 

 open by a slit-like aperture just posterior to the anus. Otherwise they resemble 

 entirely those of the male (text-fig. 6, p. 329). 



VI. General Considerations on the Structure and Growth of the 

 Urinogenital Organs. 



It having been shown by Balfour and Parker and also by Semon that the testis of 

 Lepidosteus, and perhaps also of Aclpenser, was connected with the kidney-tubules, 

 it was of extreme interest to see whether this were the case also in Polypterus, in many 

 respects the most archaic of recent Teleostomes. 



No such connections as a matter of fact exist. The products of the testis pass out 

 by a well-developed duct, which, running the same course as the ureter, opens into the 

 lateral wall of the latter close to its termination (text-fig. 5). 



It is well known that the oviduct of the female Polypterus is short and is open 

 anteriorly by a wide peritoneal funnel, the ova being shed through the external wall of 

 the ovary into the body-cavity. This duct in the female runs a course similar to the 



