HERRICK, WVerves of Siluroid Fishes. 205 
no doubt supply the terminal buds scattered sparsely over the 
ventral surfaces of the whole body. 
The r. accessorius continues caudad with no change of 
relations as far as traced (half way through the body) in our 
sections. In the neighborhood of the dorsal fin its branches 
are neither larger nor more numerous than elsewhere, nor does 
the fin bear terminal buds in greater abundance than elsewhere 
on the trunk. 
The dorsal rami of the spinal nerves are of the sort typical 
for teleosts; viz., (1) a r. communicans, sensory, and (2) a r. 
spinosus, motor. Both of these run up in the intermuscular 
space between the dorsal and inter-spinous musculature and 
may anastomose with the r. lateralis accessorius. The r. spinosus 
supplies only muscles, while the r. communicans contains gen- 
eral cutaneous fibers from the spinal ganglion for the skin of 
of the dorsum and communis fibers from the r. lateralis acces- 
sorius for terminal buds of the lateral and ventral surfaces of 
the body. 
WRIGHT states (’84a, p. 366) that the r. lateralis acces- 
sorius of A. catus (his r. lateralis trigemini) is ‘‘reinforced im- 
mediately after leaving the skull by the important dorsal 
branches of the first, second and third spinal nerves, and acts 
as a collector for slenderer branches from all of the other vam 
dorsales.’’ JuGE (’99, p. 96) makes a similar statement for 
Silurus. I have shown in my contributions on Menidia and 
Gadus that the r. lateralis accessorius is in no sense a collector 
of dorsal branches of spinal nerves in these fishes, and the same 
proves to be the case in Ameiurus also. 
Inasmuch as I have found it impossible to follow the sepa- 
rate components of the brachial plexus (in particular the general 
cutaneous and communis elements), I have not worked out the 
detailed anatomy of this plexus. It is evident that the relations 
in Ameiurus melas are not identical with those of A. catus, as 
described by Wricut. So far as I have noticed, the chief dif- 
ferences of importance concern the relations of the spinal nerves 
to the r. lateralis accessorius. As we have already seen, the 
latter nerve sends a contribution to the ventral ramus of each 
