56 MESSRS. MURIE AND MIVART ON THE 
ExrEnsor COMMUNIS DIGITORUM.—This muscle arises from the common tendon attached 
to the external condyle, and from the intermuscular septa and fascia covering the 
middle of the forearm. The fibres are inserted in a penniform manner on each side of 
a median tendon, which, near the wrist, divides into two. These again unite and form 
a wide tendon on the back of the hand, which gives origin to four flat diverging 
tendons which are not united by connecting slips, and which are inserted as usual. 
In the right manus of Z. varius we found but three tendons—a fourth one, inserted 
into the fourth digit, appearing to represent the extensor minimi digiti. 
In Cuyier’s plate of this species the muscle is represented as sending four separate 
tendons to the four ulnar digits, pl. 69. fig. 1, e. 
In Galago crassicaudatus (Pl. II. fig. 8, and PI. IV. fig. 13, E.c.d) and G. allenii this 
extensor and that of the minimi digiti are in close union, the former supplying tendons 
to the four digits. In the left arm of G. crassicaudatus, moreover, the fourth tendon 
sends a slip to the fourth digit, as well as to the fifth digit, and the third tendon sends 
one to the third digit as well as to the fourth digit. These extra slips are marked 
** 4 & 3 in Pl. I. 
In Loris gracilis this and the extensor minimi digiti also appear fused into one muscle, 
which splits into six tendons. Two of these go to the fifth digit, two go to the fourth 
digit, and the other two go to the index and third digit respectively. ‘The arrangement 
of the tendons in this species is quite undefined in Cuvier’s plate. 
In Nycticebus tardigradus' the communis is also derived from the same belly as the 
minimi digiti; but the former ultimately subdivides into five tendons, whereof the 
fourth digit has two, one on its radial and one on its ulnar side. 
In Perodicticus? this muscle has four tendons, two of which go to the fourth finger, 
one to the third, and one to the fifth finger. 
Both in Zarsius, according to Burmeister®, and in Cheiromys, according to Owen*, 
the common extensor sends four tendons to the usual digits. The deeper-seated 
extensor with subsidiary tendons, which Professor Owen mentions in the latter animal, 
is evidently the same as that described by Burmeister in Tarsius, and which we take to 
represent the extensor minimi digiti. But independently of this last-mentioned muscle, 
we found in Cheiromys the indisputable extensor communis digitorum itself easily and 
clearly divisible into two fleshy bellies, more than halfway up the arm, each separate 
belly ending distally in a distinct tendon—that from the radial belly giving tendons to 
the index, third, and fourth digits, that from the ulnar belly giving a tendon to every 
digit except the pollex. The tendons, from where they diverge up to the digits, are 
more or less connected by an aponeurotic fascia, the two small tendons going to the 
attenuated middle digit (one of which comes from the ulnar belly, and the other from 
the radial one) being very intimately connected. 
1 Pp. Z. 8. 1865, p. 247. * Loe, cit. p. 36, tab. ii. fig. 11, m. 
5% Loe. cit. p. 62, tab. 3. fig. 1, no. 27, and tab. 5. fig. 2, no. 27. 4 Loe. cit. pl. xxiii. fig. 2, no. 27, 
