SUBMENTAL FILAMENTS: GYMNOTID EEL 693 
from the others of the series by a delicate cell membrane; and each 
is well supplied with nerves and blood vessels. 
The plates in each filament are arranged as myotomes and 
placed vertically to the surrounding connective tissue. The in- 
dividual plates possess papillae on both anterior and posterior 
surfaces, the surface receiving the nerves possessing the larger. 
The nuclei are arranged regularly and usually in the papillae of 
both anterior and posterior surfaces. The middle layer possesses 
neither striations nor nuclei. These last characters are very 
similar to those peculiar to Electrophorus electricus. 
Since the tissue of the submental filaments of Steatogenys 
elegans possesses the general characters of the rudimentary elec- 
tric tissues, as in Raja ocellata, and also of the specialized electric 
tissue, as Electrophorus electricus, there seems to be little doubt 
but that this particular tissue is electric tissue. Final proof of 
this must come from Golgi preparations made from fresh material. 
The function of this probable electric organ is yet unknown. 
ELECTRIC TISSUE OF OTHER GYMNOTIDAE 
Since other gymnotid material was at hand, it seemed desirable 
to look for electric tissue in the myotome region, part of which 
is occupied by electric tissue in the electric eel, Electrophorus 
electricus. 
By examining cross sections of the entire fish and paraffin sec- 
tions of tissue from the region corresponding to that occupied by 
the pseudo-electric tissue of Electrophorus electricus, from five 
species, Sternopygus macrurus, Gymnotus carapo, Adontoster- 
narchus sachsi, Kigenmannia virescens, and Sternarchus hase- 
manni, it was found that in or between the first and second mus- 
cular units of the ventral portion of the great lateral muscles, there 
was a slight degeneration of parts of the muscles. The larger 
units had been reduced to two minute oval muscles embedded in 
either strands of cartilage, or strands of cartilage and fat, and 
occupied parts of two triangular spaces, one on each side of the 
median septum just above the unit which controls the anal fin. 
No plates, special nerve fibers, or nerve endings were seen. 
