ANATOMY OF THE LEMUROIDEA. 83 
well developed as in Lemur, and presenting the very same relations to all the sur- 
rounding parts. 
e. Region of the Foot (dorsal and plantar surfaces). 
EXTENSOR BREVIS DIGITORUM '.—This muscle seems to be somewhat irregular, differing 
in the feet of the same individual. It arises from the upper surface of the cuboid, 
ectocuneiform, naviculare, and the anterior part of the os calcis, and may consist of two, 
three, or four portions, and may send tendons to the hallux and second, third, and 
fourth digits, as we found in the right foot of Lemur catta—or the second, third, and 
fourth digits only, as we found in the left foot of Lemur catta and L. varius. There is 
also a small deeper layer of muscular fibres attached to the cuboid and the fascia 
investing the interossei and metatarsals. 
In the left foot of Z. catta the extensor brevis digitorum consisted of two bellies, 
only one (the tibial one), with its superficial layers, sending a tendon to the fibular side 
of the proximal end of the first phalanx of the second digit; the second belly bifur- 
cated in the middle of the foot, its two tendons going to the corresponding joints of the 
third and fourth digits. No tendon went to the hallux. A third layer of muscle arose 
by a tendon from the cuboid, and ended in a flat muscle attached by muscular fibres to 
the surface of the interossei between the third and fourth digits, nearly to their distal 
ends. 
In the right foot of Z. varius we observed it to consist of two bellies and of three 
tendons therefrom :—one tendon to the fibular side of the index, but not joing the 
extensor longus digitorum; two more to the third and fourth digits, these also on the 
fibular sides. 
An extension of fibres to the styloid process of the fibula is found in L. ranthomystaz. 
In the right foot of L. nigrifrons it is composed of two main slips, and sends tendons 
to the second and fifth digits, which join the extensor communis digitorum, also a small 
one to the hallux. In the left foot of the same animal (PI. VI. fig. 27, H.4.d) the 
muscular fibres were pretty well fused into a single mass, but three separate tendons 
were derived, supplying the second, third, and fourth digits respectively. 
In Galago crassicaudatus (P1. II. fig. 3, and Pl. VI. fig. 25, #.0.d) and in G. allenii 
the right foot had four muscular slips and tendons, as in the right foot of L. catta. 
In Galago garnettii this muscle is essentially divided into two slips, the large and 
innermost one arising from the anterior upper (dorsal) surface of the os calcis, and is 
inserted by a rather long and strong tendon into the proximal end of the second 
phalanx of the hallux. The second slip has a similar origin, but is inserted by a much 
more delicate tendon into the second digit, in union with the tendon of the extensor 
longus digitorum. 
In Nycticebus tardigradus the extensor brevis digitorum consists of five muscular 
i ? Cuvier, 1. c. pl. 70. fig. 1,5 (in Lemur varius), and pl. 67. fig. 1,3 (in Loris gracilis). 
M 2 
