2418 MESSRS. MIVART AND MURIE ON THE [Feb. 28, 
other to the fourth digit in the right hand, but in the left hand to 
the fifth and index. 
This muscle, being quite single in our specimen, differs from that 
described by Meckel* as existing in Loris. 
The extensor ossis metacarpt-pollicis shows no trace of subdivi- 
sion in its tendon, nor any indication that it really includes (as im- 
plied in the memoir) the extensor primi internodii. 
The extensor carpi ulnaris arises by two distinct heads, one from 
the posterior and lower surface of the external condyle, the other 
(fully half an inch broad) from the posterior surface of the ulna. 
These heads unite at an acute angle, and give origin to a tendon 
which has the usual insertion. 
Muscles of the Abdomen.—As regards the psoas and iliacus, we 
were unable to determine satisfactorily their precise limits and sub- 
divisions ; nevertheless we are certain that neither the conditions 
described by S. Van der Kolk and W. Vrolik, nor those given by 
Meckel? as existing in Loris, correspond with those in our specimen. 
The most internal portion, far from being “la plus forte,” is the 
most slender. It is undoubtedly the psoas parvus, and arises by 
fleshy fasciculi from the sides of the bodies of the second and third 
lumbar vertebree, but very soon becomes entirely tendinous. Its long 
thin tendon, having an aponeurotic extension proceeding from the 
inner border, goes towards the pelvis, is closely applied to the muscle 
beneath, and finally inserted into the ilio-pectineal eminence imme- 
diately above the acetabulum. In Tarsius’ the tendon of the psoas 
parvus bifurcates. 
The large muscular mass beneath the above tendon appears to re- 
present the iliacus. It arises, however, from the sides of the bodies 
of the lumbar vertebrze below the third, and from the front of the 
sacrum (being separated from the pyriformis at its origin by the 
sacral plexus), but it has no origin from the ilium ; the insertion is 
normal. 
Another large muscle, which we suppose must be considered as the 
psoas magnus, arises behind the last described (the ventral surface 
of the body being towards the observer), from the bodies and trans- 
verse processes, at their bases, of the two last dorsal and six upper 
lumbar vertebrze, and is inserted as usual. At its origin it has nu- 
merous tendons interspersed in its muscular substance, and is closely 
connected with the next to be described. 
This muscle, which we provisionally call *quadratus lumborum, 
arises from the two transverse processes of the lumbar vertebree, 
from about the fourth downwards, and is inserted into the crest of 
the ilium immediately above what appeared to be the scansorius. 
Above it is so closely connected with the psoas magnus that the cor- 
rect determination of their limits requires further examination. 
The superficial abdominal muscles present nothing worthy of re- 
mark, excepting the rectus. This is continued forward as a narrow 
band on each side of the sternum, parallel with and about one-fifth 
1 Anat. Comp. vol vi. p. 324. 2 Loe. eit. p. 374. 
> Burmeister, p. 67, t. 4, fig. 2. no. 1. 
