1892.] The Head of an Embryo Amphiuma. 671 
THE HEAD OF AN EMBRYO AMPHIUMA. 
By J. S. KINGSLEY. 
The following is a preliminary account of some studies of a 
single stage of Amphiuma means before hatching. For the 
material I am under great obligations to Prof. O. P. Hay, of 
Irvington, Indiana. I must also return my thanks to Prof. 
Dr. Robert Wiedersheim, in whose private laboratory in the 
University of Freiburg i-B., my studies were conducted. Only 
one who has enjoyed the privilege of working with him can 
appreciate his many kindnesses and extreme helpfulness. 
EXTERNAL APPEARANCE.—The general appearance of the eggs 
has already been described by Dr. Hay, and is strikingly sim- 
ilar to that of Ichthyophis as described and illustrated by the 
cousins Sarasin. This resemblance is strengthened by the 
fact that the cord connecting the eggs is spirally twisted as in 
the Ceylonese Gymnophione described by them. 
The external description of the embryo Amphiuma has been 
correctly described by Hay in most points, but in a few respects 
my specimens differ from his description. According to him 
“the gills consist of three pairs, and are of the simply pinnate 
form. . . Only once have I observed any of these lateral 
filaments to divide. . . Three gill slits are still open.” The 
figures which illustrate this are strikingly like those of the 
Sarasins of the branchie of the Ichthyophis larve. In the 
larvee which I studied the resemblance is not so striking. The 
three gills of either side are united at the base into a common 
trunk, the gill filaments are not bipinnately but irregularly 
arranged, and in none of my specimens have I found more 
than one gill cleft open. (Cf. infra.) 
CHONDROCRANIUM.—The cartilaginous skull, as it appears in 
a wax reconstruction after Born’s method (and compared with 
dissections), is more slender than in Hay’s figures; it also pre- 
sents minor differences in several other respects from his rep- 
