44 MESSRS. MURIE AND MIVART ON THE 
first head, arises by fleshy fibres from the upper and anterior third of the ulna, below 
the lesser sigmoid notch, and from the interosseous membrane. 
These three form a broad tendon along with the flexor longus pollicis just above the 
wrist joint, which ultimately subdivides as in Lemur. 
Although Van der Kolk and Vrolik do not mention this muscle in Loris separately 
from the flexor longus pollicis or the peculiarity in the tendons, yet we ourselves find 
in Loris gracilis that it has origin and tendinous insertions almost like Mycticebus 
tardigradus, differing in that it forms exclusively the tendon of the fourth and fifth 
digits and contributes bridge-like slips to the three radial ones (woodcut, fig. 14). 
In Nycticebus tardigradus’ it may be regarded as having but one extensive head of 
origin, which, after receiving its slip from the flexor sublimis, bifurcates, sending a 
tendon to the pollex, another delicate one to the index, another to the fourth, and 
exclusively forms the fifth (see diagram, fig. 15). Professor Huxley* did not find the 
delicate tendon which joins the index tendon of the flexor longus pollicis either from 
this or the flexor sublimis. 
Van Campen® describes this along with the flexor longus pollicis as one muscle in 
Perodicticus. He says that it consists of two separate parts, the tendons of which 
unite together, arising from the condyle, &c., and ending in four tendons going respec- 
tively to the pollex, the third, fourth, and fifth digit. The author remarks that the 
index digit receives no tendon. This might almost have been anticipated from the all 
but aborted condition of the index digit. 
The flexor profundus and the flexor longus pollicis are described by Burmeister in 
Tarsius* as one enormous muscle, they together having five heads of origin. 
The first springs from the internal condyle beneath and attached to the flexor carpi 
radialis; its under surface is tendinous. 
The second head comes from the inner side of the radius, and joins the first. 
The third head springs deeply under and close to the first, from the anterior surface 
of the internal condyle. 
The fourth head comes with oblique fibres from the upper border of the ulna, and 
lower down joins the third head. 
The fifth head, which is the largest, springs from the olecranon and upper end of the 
ulna, joining the third and fourth heads and then receiving the slip from the flexor 
sublimis. After this it joins the tendon of the first and the second heads. ‘Then the 
thumb and the index finger have their deep flexor tendons mainly derived from the first 
and second heads. Those of the fourth and the fifth fingers mainly come from the 
tendon of the fifth head, that of the middle finger mainly from the third and fourth 
heads. 
' P. Z. 8. 1865, p. 245, fig. 2. 
* Hunterian Lectures, 1864, Med. Times and Gazette, Aug. 6, vol. ii. no. 756, p. 145. 
* Loe. cit. p. 36. * Loe. cit. pp. 60 and 61, tab. 3. figs. 1 and 3. no. 34 &e. 
