ANATOMY OF THE LEMUROIDEA. 13 
In Galago crassicaudatus (see Pl. II. fig. 3, and Pl. III. fig. 6, O,f'), although thin, it 
is a well-developed sheet, and nearly throughout muscular. Its continuation into the 
ear-muscles would seem to aid in producing the peculiar epicranial movements so cha- 
racteristic of this species and its allies. In the specimen of G. garnettii dissected by us, 
it was remarkably thin, but otherwise similar to the above, as we observed also in 
G. allenii. 
The ATTOLLENS AUREM is represented by a broad and thin muscular layer, united above 
with the occipito-frontalis, and inserted into the upper part of the tragus. 
In G. crassicaudatus, as in some degree also in G. garnettii and G. allenii, it is very 
strongly marked, being in fact a continuation of the broad occipito-frontalis. It seems 
to spread out as a thin and delicate sheet over the anterior part of the dorsum of the 
external ear for at least half its length. 
Van Campen' mentions that in Potto its fibres mingle with the occipito-frontalis. 
Our description of this muscle in L. catta seems to agree with Burmeister’s account 
of the same muscle in Tarsius’. 
ATTRAHENS AUREM.—This is represented by some rather indistinctly separated fibres of 
the lower border of the occipito-frontalis muscle, which are inserted into the anterior 
part of the concha. 
In Galago crassicaudatus (Pl. II. fig. 3, At. a) this (as well as the other auricular 
muscles) is well developed ; and its fibres, imbedded in a thin sheet of fascia continuous 
above with the attollens and occipito-frontalis, arise from the posterior margin of the 
orbit, and are inserted as in Lemur. ‘The fibres are most marked and numerous towards 
the helix. In some respects it may be said even to be stronger in G. garnettii. 
In Perodicticus® it is short. 
In Tarsius* it is less developed than in G. crassicaudatus, in this rather approaching 
to the Lenwrs. 
RETRAHENS AUREM.—This is a narrow band of muscle arising from the superior curved 
line of the occiput as far forwards and inwards as its junction with the temporal ridge. 
It is inserted into the posterior part of the concha. 
In G. crassicaudatus (Pl. III. fig. 6, Re.a', Re.a’, Re.a*) the retrahens aurem is repre- 
sented by at least three separate slips, much in the manner described by Burmeister in 
Tarsius (see below). ‘The anterior slip is the largest. 
In Perodicticus* it appears to be represented by two thin slips of muscle, but with 
the same attachments as in Lemur catta. 
In Tarsius, Burmeister* says, there are four muscular bundles which compose the 
retrahens aurem. ‘The first and largest arises from the upper part of the ligamentum 
nuche, the middle line of the occiput, and posterior part of the sagittal suture, becoming 
narrower as it reaches the upper part of the ear. The three other smaller bundles lie 
1 Loc. cit. p. 24. * Loc. cit. p. 81, tab. 3. fig. 1, 7. % Loc. cit. p. 24, 
+ Loc, cit. p. 32, tab. 3. fig. 1 (1). 5 Loc, cit, p. 32, tab. 4, fig. 1, K. 1, 2, 3, 4. 
