3d. The fibrous sheaths are destined to confine the tendons in their passage upon the bones, where they are reflected, and generally wherever by muscular contraction they would be made to deviate and consequently transmit with difficulty to the bones the motion they receive from the muscles. They may be divided into two kinds; one receives and transmits the tendons of many muscles united, as is seen at the wrist, the instep, &c.; the other, like that of the fingers, is destined for a single tendon, or two only. 4th. The aponeuroses are a kind of fibrous nets more or less broad, entering always into the system of locomotion, and so arranged that they sometimes form coverings for different parts, and sometimes furnish the muscles with points of insertion. Hence the aponeuroses of covering and the aponeuroses of insertion; each of them is divided into species. The aponeuroses of covering are placed sometimes around a muscle, to which they serve as a general sheath, as we see on the thigh, the fore-arm, &c.; sometimes upon certain muscles which they partially retain in their respective places, as that which goes from the posterior and superior serratus minor to the anterior and inferior, as the abdominal aponeurosis, as that situated anteriorly to the solæus, behind the deep muscles of the leg, &c. The aponeuroses of insertion are sometimes with surfaces more or less broad, as in the attachments of the triceps femoris, the rectus, the biceps, &c.; sometimes with fibres separate from each other, and giving attachment by each of these fibres to a fleshy fibre, as at the superior insertion of the iliacus, of the anterior tibialis, &c.; sometimes finally in the form of an arch, and then at the same time that they give the muscles points of insertion, they allow vessels to pass under them, as in the diaphragm, the solæus, &c. II. _Of the Fibrous Organs in the form of Fasciæ._ The fibrous organs arranged in fasciæ are, 1st, the tendons; 2d, the ligaments. 1st. The tendons are found at the origin, insertion or middle of the muscles. They are either simple, in the form of elongated cords, as in the peronæus, the tibialis, and almost all the muscles, or compound, as in the rectus, the flexors, &c. 2d. The ligaments strengthen the osseous or cartilaginous articulations, around which they are found. They have regular fasciæ, as the lateral ligaments of the elbow, the knee, the jaw, &c.; or irregular fasciæ, as those of the pelvis. III. _Table of the Fibrous System._ We can in the following table present at a single view the classification of the fibrous organs that I have just pointed out.