172 BRODE. [Vou. XIV. 
starting-point for the development of the organs of special 
sense in the higher animals, not excepting even the eyes of ver- 
tebrates.”! He also advocates the view that “the ancestral 
segmental sense organs were not limited to a single pair of 
lateral lines, but to several paired lines symmetrically placed 
on the dorso-lateral and ventro-lateral surface.” ? 
Objections to the homology held by the investigators above 
mentioned have been brought forward by a number of men, 
including Balfour, who in regard to Capitellidae says: “I am 
not inclined to think that there is a true homology between 
these organs and the lateral line of Vertebrata.” ® 
It must be admitted that in the adult form there is a notable 
difference between the systems of organs in annelids and ver- 
tebrates. If we consider the annelid organs as the starting- 
point, we find some points of similarity, such as the metameric 
arrangement and the general plan of structure of all the organs, 
which may prove of much importance in the further study of 
the lateral-line system. 
THE UNIVERSITY OF CHICAGO, 
June, 1896. 
1C. O. Whitman, Journ. of Morph., pp. 592, 593- 
2 [bid., p. 595- 
3 F. M. Balfour, Complete Works, Vol. III, p. 535, note. 
