GANGLIA AND NERVES OF SQUALUS 53 
minalis, in three chief divisions: the Gasserian and the profun- 
dus root complex, the VII—VIII root complex, and the [IX—-X 
root complex. 
The most striking features of the embryonic ganglia of Squalus 
in comparison with Ameiurus and Lepidosteus (Landacre, ’10 
and 712) are, first, the presence of three distinct lateral line 
ganglia on X and, second, the immature condition of the gen- 
eral cutaneous ganglia on X and the absence of a separate ramus 
auricularis, this nerve being fused with the ramus lateralis X.1. 
The presence on IX of a general cutaneous ganglion in several 
vertebrate types including apparently man, and, particularly, 
the presence of general cutaneous ganglia and fibers in both 
VII and IX in Petromyzon (Johnston, ’05) would lead one to_ 
expect them in Squalus. A careful search failed to demon- 
strate them. However, since the general cutaneous compo- 
nent on X matures very late and the jugular ganglion is always 
small and ill defined, a study of older material may show cu- 
taneous ganglia and fibers in both VII and IX. 
The special visceral or gustatory cells on VII, IX and X 
cannot in a 22 mm. embryo be distinguished sharply from the 
general visceral or branchial cells, although all of the bran- 
chial ganglia on X are still in contact with their respective epi- 
branchial placodes. In a 20 mm. embryo (Reed, ’16) the proc- 
ess of contribution of cells by the epibranchial placodes and 
their metamorphosis into ganglion cells can be observed. 
The terminal buds or gustatory organs seem to be late in 
appearance. They are present in the 30 mm. embryo but 
material fixed in vom Rath is not particularly favorable for their 
identification and their number and position are not described 
in this paper. Taste buds could not be identified with certainty 
in the embryo plotted. 
The branchial ganglia of Squalus are well isolated in compari- 
son with Ameiurus and Lepidosteus at similar stages. All of the 
visceral ganglia on IX and X and most of the lateral line gan- 
glia are in finger-like processes extending ventrally above their 
respective gill slits. In Ameiurus and Lepidosteus and particu- 
larly in Rana there is a large mass of cells from which the suc- 
