BRANOCHIAL SENSE ORGANS IN ICHTHYOPSIDA. 139 
the development that the so-called dorsal branch (supra-bran- 
chial nerve) forms late in the development, and arises solely 
by the necessity of extension and increase of the branchial 
sense organs, with which it is solely concerned, the ventral 
branch as such is probably solely concerned with the innerva- 
tion of the gill-clefts. 
A few words may be devoted to the researches of Bodenstein! 
and Solger,” which have led to the conclusion that in the sense 
organs of the lateral line in Teleostei nerve strands connecting 
the various sense organs together are present. From the account 
of the development given here such a connection might be ex- 
pected to occur, for I have shown that the “lateral line” has 
arisen solely by the extension and multiplication of the primitive 
branchial sense organs of the vagus; they are, as we have seen, 
connected in development, being formed from one continuous 
sensory rudiment, and as they form one physiological whole 
we could expect a connection in the adult. Although I have 
not attempted here to give an account of the development of 
the ‘lateral line”’ in Teleostei, I may perhaps be allowed a 
few words on it as it seems to confirm the researches under 
discussion. 
In this case in the growth backwards of the sensory 
rudiment there are found thicker portions, which are seg- 
mental, and thinner portions connecting them. The nerve is 
split off along the whole length, just as in Elasmobranchs. 
The thicker portions give rise to the sense organs, the thinner 
portions only to nerve structures, and probably to those 
connecting strands described by Boderstein and Solger. 
REMAINS oF BrancHIAL SENSE OrGANs IN HIGHER 
VERTEBRATES. 
Prof. Froriep’s paper, leaving aside the small error just 
mentioned, is a very interesting and very important addition 
1 Bodenstein, E., “Der Seitencanal von Cottus Gobio,” ‘Zeit. f. wiss. 
Zool.,’ Bd. xxxvii, Heft 1. 
? Solger, “ Ueber die Seitenorganen Ketten der Fische,” ‘ Zool. Anzeig.,’ 
1882, No. 127, p. 660, 
