No. 2.] THE MORPHOLOGY OF DERO VAGA. 165 
line described by Semper is a cell cord in which sense organs 
are found, the similarity to the vertebrate “ Anlage”’ is striking, 
to say the least. 
In a preliminary paper Vejdovsky 1 notes the occurrence of 
a “lateral line” or lateral cord in Anachaeta, and thinks it 
probable that it functions as a sympathetic nerve, and, being 
connected with the commissure, suggests that it might be 
called a “vagus nerve.” Timm? has noted the occurrence of 
this cell cord in Phreoryctes, and Bilow finds it in Lumbri- 
culus, and thinks it is undoubtedly nervous in its character. Rei- 
ghard* found the cells in Dero, but could not trace the cord as 
far forward as the commissure. Stolc 5 called it a lateral nerve 
and thought that it probably arose from the two large cerebral 
nerves. 
Vejdovsky® in his valuable monograph considers that this 
structure is of general occurrence in the Oligochaeta, and _ pro- 
poses that the term ganglion cell cord (‘ ganglienzellstrange ’’) 
be applied to it in view of the fact that its homology with the 
lateral line of vertebrates has not been thoroughly established. 
He says that the connection of the cord with the commissure 
is made out with great difficulty. In many worms the cord in 
the anterior segments is differentiated into fibres which con- 
nect with the brain,’ while in the higher forms the undifferen- 
tiated cells merge into the brain or rather into the commissure 
near the point where it leaves the brain. The cells which make 
up this cord are mostly unipolar, and only in Enchytraeidae did 
he find bipolar and multipolar cells. Lateral branches, some- 
times composed of ganglionic cells and sometimes of fibres, are 
given off from the main cord. 
1 F. Vejdovsky, Vorlaufige Mittleilungen iiber die fortgesetzten Oligochaeten- 
studien, Zool. Anz., 1879, p. 184. 
2 R. Timm, Beobachtungen an Phreoryctes menkeanus Hoff. und ais, Arbeit. 
a. d. Zool.-Zoot. Inst. Wiirzburg, Bd. VI, 1883, pp. 131, 132. 
3 C. Biilow, Die Keimschichten des wachsenden Schwanzendes von ZLumbriculus 
variegatus, etc., Zeit. f. wiss. Zool., Bd. XXXIX, 1883, p. 75. 
4 J. Reighard, Anatomy and Histology of Awlophorus vagus, Proc. Am. Acad. 
Arts and Sct., Vol. XX, 1884, p. 104. 
5 A. Stolc, Dero digitata, etc., p. 91. 
6 F. Vejdovsk¥, System und Morphologie der Oligochaeten, 1884, pp. 93, 94. 
" Le, Vat Als Fiesty: 
