ANATOMY OF THE LEMUROIDEA. 15 
In Loris gracilis it is rather small’. 
In Tarsus, according to Burmeister’, it is double. The outer or anterior portion springs 
from the anterior half of the linea semicircularis of the frontal and temporal fossa. The 
inner and hinder part springs from the entire length of the same linea semicircularis. 
In Cheiromys, Owen’ says it derives many fibres from the strong temporal fascia. 
MasseTeR*.—This muscle is rhomboidal in shape and arises from the whole length of 
the zygoma. It is inserted into the concavity outside the ascending ramus of the man- 
dible and into its angle, pretty well shown in Cuvier’s figure (pl. 69. fig. 1, 7) of Lemur 
varius. 
Substantially the same in the Galagos: that of G. crassicaudatus is shown in Pl. II. 
fig. 3, and Pl. III. figs. 5 & 6, Ma. In Loris gracilis it is of moderate size’. In Tarsius® 
it consists of two layers—an outer and anterior, and an inner or posterior one. 
Owen’ says that in the Aye-Aye the masseter consists of two portions, an external 
and an internal. ‘“ The external fibres pass downward almost parallel, to be inserted 
into the lower border of the posterior half of the mandible; they are separated by a 
thin glistening aponeurosis from the internal portion, the fibres of which pass a little 
forward as well as downward. ‘These two portions blend together anteriorly, the inner 
portion is inserted into the outer surface of the broad ascending ramus. There is no 
trace of an accessory masseter such as exists in many Rodents.” 
ORBICULARIS ORIS.—In Lemur catta this is a very elongated narrow muscle, agreeing 
with the length of the jaws *. 
It is with some difficulty the fibres can be separated from those of the cheek and 
nasal muscles® in the Grand Galago (PI. II. fig. 3, and Pl. III. fig. 5, 0.0). 
In Loris gracilis it is relatively larger than in Lemur, as shown by Cuvier in the 
sixty-seventh plate of his ‘ Planches,’ fig. 1,/. In Tarsius' it is very weak. 
Van der Hoeven speaks of its being much intermixed with the other lower facial 
muscles in the Potto”. 
Nasal MuscLES.—In the Lemuroids generally, the naso-labial region being more or 
less elongated and produced, the nasal muscles proper, with those of the upper lip, 
form a broad and very extensive sheet reaching from the orbits to the nostrils. This 
sheet appears to represent the conjoined zygomatici, levator labit superioris aleque nasi, 
&c. (Pl. II. fig. 3, Na.). 
The BUCCINATOR in the genus Lemur is also somewhat elongated in shape ”. 
} Cuvier, pl. 67. figs. 1 and 2, b. ? Loc. cit. p. 33, tab. iv. figs. A, Ar. > Loe. cit. p. 59. 
* Meckel, J. c. p. 752, considers it relatively more developed in the Lemurs than in Man. 
* Cuvier, 1. c. pl. 67. figs. 1 and 2, 7. ° Loc. cit. p. 32, tab. 3. fig. $, and tab. 4, fig. 9, $5. 
7 Loc. cit. p. 59. 8 Cuvier, J. c. pl. 69. tig. 1, U. 
* Meckel, op. cit. vol. viii. p. 751, alludes to this circumstance in speaking of the muscles of the lips in Qua- 
drumana generally, and further notices the intimate relation of the cutaneous fibres with them. 
Loe. cit. p. 31, tab. 3. fig. 1, ¢. N Loe. cit. p. 24. © Cuvier, 7. c. pl. 69. fig. 1, 7. 
