1866. | Zoology, Animal Physiology, gc. 127 
remarkable, and even more complex than in the ostrich. At first 
he was disposed to think it threw some doubt upon the explanation 
he had pieviously given of the reason for such an arrangement in 
the bird’s leg, as there did not appear so much reason for it in the 
case of the crocodile; but he subsequently came to an enormous 
deep muscle (the extensor femoris caudalis), originating from the 
transverse and inferior spinous processes of the caudal vertebree, and 
inserted into the back of the upper part of the femur, and into a 
great round tendon, which, passing down the back of the femur, is 
inserted by a common aponeurosis into the outer condyle and the 
head of the fibula. The effect of the interlacing of the tendons of 
the various muscles is to produce simultaneity of action among 
them, as in the ostrich; and in the crocodile there seems to be a 
similar principle involved. The crocodile, resting on mud, pro- 
gresses chiefly by using his hind feet as paddles; and in this use 
of them, the great caudal extensor of the thigh is the most powerful 
and important muscle employed. The simultaneity of action of all 
parts of the leg, rendered necessary by the employment of go 
powerful a muscle, is fully secured by the interlacing of the tendons, 
which renders it impossible for one set of muscles to act without the 
others being also exerted. 
M. Matteucci gives an account, in ‘Comptes Rendus,’ of some 
experiments upon the electro-motor power organs of the Torpedo, in 
a state of repose, z.e. which gave no sensible discharge to a delicate 
galvanometer ; and he finds under certain circumstances that a con- 
stant current is present, which deflects the galvanometer with a 
persistent deviation. This electro-motor power notably increases 
after the piece of the organ has been forced to give a discharge by 
irritating the nerves. And in torpedos taken in warm seasons, when 
out of water they very rapidly lose their electric function, and the 
electro-motor power of which is almost nil, by irritating the nerves 
of the organ, or by rounding the fourth (electric) lobe, the electro- 
-motor power suddenly reappeared, and persisted for some time. 
M. Matteucci has endeavoured to verify the observations of M. 
Robin, made some years back, with regard to the organs analogous 
to the electric organ of the Torpedo, which he supposed to be pos- 
sessed in certain rays. He had already tried without success, but 
supposing the failure might possibly be owing to his having operated 
on very small and sluggish fish, he, with the assistance of M. 
Schiff, operated upon a tolerably large and'vivacious ray, and haying 
forced the fish to a series of strong contractions, M. Matteucci 
obtained, by the galvanoscopic frog, the exposed nerve of which 
was placed upon the organ in question, manifest signs of electric 
discharges. ‘This experiment he pledges himself to repeat and 
corroborate, and remarks that the difference in the dimensions and 
number of the elementary cellules, and the nerves of the electric 
