ANATOMY OF THE LEMUROIDEA. 37 
In Zarsius Burmeister remarks that the four tendons of this muscle reunite into a 
single tendinous sheet on the back of the manus, from which sheet the four extensor 
tendons are given off. 
EXTENSOR MINIMI DIGITI.—A very small muscle with a very long tendon arising from 
the external condyle and the intermuscular septa. Its delicate tendon runs down 
beneath the annular ligament, and divides into two, which go to the ulnar side of the 
fourth and fifth digits respectively; that which goes to the fourth digit is joined by a 
delicate branch from the extensor indicis. 
Meckel says in the Lemurs it attaches itself sometimes to the fourth and fifth digits. 
On the left side of Z. varius the extensor minimi digiti went to the fourth digit only, 
without being joined by another tendon from the indicis. In Cuvier’s figure of this 
species, two tendons go to the fourth and fifth digits as usual, pl. 69. fig. 1, e'. 
In Galago crassicaudatus this muscle is so united with the extensor communis 
digitorum as to be very little seen. Its tendon receives no slip from the extensor 
indicis, but bifurcates, its branches going to the fourth and fifth digits as in Z. catta 
(Pl. II. fig. 3, and Pl. IV. fig. 13, #.m.d). 
In G. allenii it also arises in common with, but rather to the outer side of, the 
extensor communis digitorum. Its tendons, two in number and very delicate, are 
inserted as in L. catta, but without the extra indicial slip. 
According to our observations, both in Loris gracilis and Nycticebus tardigradus’ it 
also has a common origin with the extensor communis, but seemingly has only one 
tendon, which goes to the fifth digit. 
It appears to be inseparably united with the extensor communis digitorum in the 
Potto’. 
Burmeister® says, at its origin it is in close union with the extensor carpi radialis 
brevior, its tendon comes off higher than the extensor communis, and, splitting, proceeds 
to the fourth and fifth digits. 
In Cheiromys it is described by Owen‘ as a slip of the extensor communis with 
tendons to the fourth and fifth digits; but we found that in this species the muscle is 
well developed, though in close union at its upper part with the belly of the extensor 
communis digitorum. Its tendons are as in L. catta, except that there is no slip from 
the index. 
EXTENSOR CARPI ULNARIS.—This muscle is about the same size as the extensor com- 
munis, but has a much stronger tendon. It arises from the external condyle, the 
margin of the ulna, the septa, and aponeurosis, and is inserted into the base of the fifth 
metacarpal. 
The same in Z. varius and L. nigrifrons; but in L. canthomystax its tendon divides, 
1 Pp. Z. 8. 1865, p. 247. * Loe. cit. p. 36, pl. ii. fig. 11, m. 
* Tarsius, p. 62, under head of extensor com. digitorum, tab. 3. fig. 4. 35, 
* P. 62, under head of extensor digitorum communis, pl. xxiii. fig. 2. 27a. * 
