ANATOMY OF THE LEMUROIDEA. 31 
The inner head is more or less divisible into two muscles, and is described as such by 
Burmeister. 
3. The first or upper part of the inner head arises from the postero-inner side of the 
head of the humerus, as high as just beneath the insertion of the subscapularis, and 
considerably above the insertions of both the teres major and the short part of the 
coraco-brachialis. 
4, The second or lower part of the inner head, which is spoken of by Burmeister as 
a distinct muscle, the ‘“ Anconeus sextus,” is separated from the last-described part by a 
more or less marked interval, where the muscular spiral nerve passes. It arises from the 
inner side of the lower half of the shaft of the femur, the supinator ridge, and internal 
condyle, and occupies part of the intercondyloid space at the back of the humerus. 
All these portions unite together and are inserted into the olecranon process of the 
ulna; but the second and third portions unite together very high up indeed. The long 
head joins at about the middle of the arm; the anconeus sextus of Burmeister joins 
the common mass at the olecranon, but is more or less connected with the rest of the 
muscle for the lower half of its extent. 
Cuvier, in his posthumous ‘Planches de Myologie,’ distinguishes the usual three 
parts of the triceps and the dorso-epitrochlear, marked respectively in pl. 68. fig. 2, and 
pl. 69, fig. 1, of Lemur varius, by t, t}, £2, and ¢*. The lower division of the internal 
head of the triceps is distinguished as the “‘ancone interne,” and marked wu’. No external 
anconeus is separately indicated. 
We ourselves have found itin Lemur varius, L. niger, and L. nigrifrons as in L. eatta; 
also in the Galagus. Slight individual variations exist as to how far the anconeus sextus 
goes up—one being like what is mentioned in Nycticebus. The several portions of the 
triceps are figured in G. crassicaudatus (Pl. I. fig. 3, Pl. IIT. figs. 5, 6, & 7, and Pl. IV. 
Bela S14, 2°72", T°, 1%). 
In G, peli* it is described as consisting of six parts, namely, the three ordinary heads, 
together with an anconeus quartus (the ordinary anconeus of Man), the dorso-epitrochlear, 
and a distinct lower separation of the internal head. 
In Nycticebus we did not find an anconeus sextus distinctly differentiated; for the 
musculo-spiral nerve pierces what is evidently the ordinary internal head. 
In the Potto the anconeus sextus is not mentioned by Van Campen. 
In Tarsius Burmeister? describes what answers to the lower part of the internal head 
of Man, as quite distinct, under the name of anconeus sextus. His arrangement of the 
great extensor of the forearm is as follows :— 
A. Anconeus primus‘, or longus (the scapular head of Man). 
B. Anconeus secundus‘ (the external head of Man). 
C. Anconeus tertius* (the upper part of the internal head of Man). 
bo 
to 
Q 
1 Kingma, loc. cit. pp. 25 and 26. ? Loc. cit. p. 53. 3 Tab. 3. fig. 1. : 
4 Tab. 3. fig. 1. 220. 5 Tab. 3. fig. 2. 22c. 
