DR. MOXON, ON MOTOR NERVE. 237 
tive tissue exists in invertebrata—certainly not in the insect 
larva in question—and so this source of error is absent. 
Then, again, the small size and transparency of these larvze 
enable an observer to examine the muscles during the life of 
the creature, and the muscle in moving moves the nerve 
attached to it, so as to render abundantly evident the fact of 
its attachment, and to enable the observer to be certain of 
the attachment or otherwise of structures lying in its imme- 
diate neighbourhood. 
The muscle to which I would direct attention is the re- 
tractor antennz of the larva of a gnat common in ponds in 
the spring of the year. This is a fibre about +,),, of an inch 
wide, provided with sarcolemma, which itself has nuclei upon 
it. The transverse striation of the fibre is complete and 
regular. That the nuclei are upon the sarcolemma I have 
not known from this muscle; but in larve which have been 
made dropsical by forty-eight hours’ confinement in airless 
water (after Doyere’s method) I have seen in muscles of the 
trunk the appearance shown in fig. 4 (Pl. IV), the sarcous 
substance torn across, and the sarcolemma bearing nuclei, 
extending between the broken ends of it. 
From the antennal lobe of the insect’s cephalic ganglion 
comes the antennal nerve, a nerve of some size, which has 
a neurilemma-sheath provided with nuclei (hk); at some 
distance from the base of the chitinous antenne the nerve 
expands to form a long spindle-shaped ganglion fullof ganglion- 
cells (a), and then in this ganglionic condition enters the 
antenne, the cells still discernible through the chitin. About 
two thirds of the distance from the encephalon to the ganglion 
the nerve gives at right angles to its own course a branch (8) 
smaller than itself; this proceeds at once to the outer edge 
of the antennal muscle and joins the outer edge; the motor 
nerve is just so long as to allow the play of the muscle in 
its frequent contractions. 
At the point where the motor antenne nerve leaves the 
sensory antennal nerve there is a corpuscle (f), whether 
neurilemmar or no I cannot say, also there are two small 
nuclear corpuscles (h’) close to the end of the nerve on the 
muscle. The union of the neurilemma and sarcolemma is a 
direct continuity. 
I have very carefully examined the point of union in order 
to ascertain what is the relation of the proper fibre (axis 
cylinder) of the nerve with the sarcous substance of the 
muscle-fibre. The muscle in contracting preserves a straight 
border, beautifully distinct from the sinuous folds (gg) into 
which the sarcolemma is thrown. During extreme contrac- 
tion the sarcolemma is gathered up into wrinkle-like folds, 
