199 



In unhatched specimens of Lepidosteus of seven days, and in newly 

 hatched ones of nine days (7Vg mm in length), the pronephros pre- 

 sents on each side three outer and three inner ciliated funnels. 



The three outer funnels open into the general body-cavity, the 

 first one lying at the anterior end of the organ, the second roughly 

 about mid-way along, and the third near the posterior end of the pro- 

 nephros. 



The three inner funnels open as in Acipenser or Amia into a 

 capsule which represents a completely shut off portion of the body- 

 cavity, and it may be further noted of them that each of the three 

 lies approximately in the same transversely vertical plane as the cor- 

 responding outer one. 



Into the capsule there projects from the under side of the aorta 

 a long folded glomerulus, connected by small branches with that vessel. 

 As in the other two Ganoids described by Jungersen the glomerulus 

 is made up of a number of small and large lappets, and as in Aci- 

 penser it extends some little distance posterior to the capsule. 



At a later stage the number of outer and of inner funnels be- 

 comes reduced to two on each side. 



From a table of the condition in a number of embryos it may 

 be concluded that the period when this occurs is subject to indivi- 

 dual variations. This table also shows that it is the central funnels 

 which close, for in some cases the middle inner funnel is still open 

 while its corresponding external fellow is closed. My former ac- 

 count would appear to require correction on this point also. 



Thus, in one embryo of 9 mm on both sides the middle outer 

 funnel has completely disappeared, while on the left side the middle 

 inner funnel is persistent, and on the right it would appear to have 

 closed. 



In an example of 11,5 mm in length there are on the one side 

 two outer and three inner funnels, whilst on the opposite side the 

 central inner funnel is closing. 'In embryos of 14 mm the reduction 

 is completed. The outer funnel apparently always disappears before 

 the corresponding inner one. 



The figures of the pronephros of Amia, recently published by 

 Jungersen, would serve fairly well for that of Lepidosteus. Figures 

 2 and 3 of his recent paper represent exactly the conditions seen in 

 transverse sections passing respectively through inner and outer funnel 

 of Lepidosteus. But in order to adapt it to Lepidosteus figure 1 

 would require alteration. As in Amia and Acipenser the pronephros 

 itself consists of somewhat contorted outer and inner limbs, corre- 



