156 
ADAM SEDGWICK. 
Malpighian body, the structure developed independently 
in the intermediate cell mass certainly giving rise to more 
than the Malpighian body. 
I now pass to the development of the secondary tubules, 
&c. Fiirbringer^ derives them also from peidtoneal in- 
growths. He has not, however, given, so far as I know, any 
figures showing this. I have examined this point with 
some care, but have quite failed to discover any traces of 
these secondary ingrowths. 
The secondary tubules appear to me to arise from a small 
mass of cells. They occupy, at a slightly earlier stage, the 
position of in fig. 11. In this figure the vesicular 
rudiment of a secondary tubule has appeared in this mass of 
cells. The tertiary and quaternary, &c., tubules appear to 
arise successively at a slightly later stage from similar 
small masses of cells, which are always placed just dorsal to 
the last-formed tubule. The later development of these 
secondary, tertiary, &c., Wolffian tubules is very similar to 
that of the primary. 
The time of development of the primary tubules relatively 
to that of the secondary, &c., tubules varies in different parts. 
Anteriorly the primary tubule is much more developed (in 
fact, has acquired an opening into the Wolffian duct, not 
figured in fig. 11), before the first trace of the secondary 
tubule arises (fig. 11) ; while posteriorly a secondary and ter- 
tiary tubule have appeared almost before the primary tubule 
has lost its vesicular structure (fig. 13). 
The development of the secondary, &c., Wolffian tubules in 
the chick appears to be very much abbreviated. 
Whatever may have been their development in phylogeny, 
no light is thrown upon it by their ontogeny. Nor even can 
a comparison be made between their development in the 
chick, and that in other forms in which it is possible to 
suppose the development is less abbreviated. In Elasmo- 
branchs the secondary tubules, as Balfour^ has shewn, 
develop in connection with the Malpighian bodies of the 
primary tubules, as outgrowths from them, which eventually 
open into the collecting tubules of the segment in front. 
Neither Balfour nor, as far as I know, any other observer, 
have elucidated the development of the tertiary, &c., tubules 
in Elasmobranchs. 
In the Salamander Furbringer^ has shewn that they 
develop as they do in the chick from cell masses closely 
* Loc. cit. 
’ Balfour, < Elasmobranch Fishes/ 
Loc, cit. 
