16 MESSRS. MURIE AND MIVART ON THE 
It is well marked though not readily distinguished from the posterior fibres of the 
orbicularis oris in Galago crassicaudatus (Pl. I. fig. 3, and Pl. III. fig. 5, Bu). 
In Perodicticus* it is very thin, otherwise much as in Man. The duct of Stenon 
passes through it above. 
In Zarsius® it springs from the under surface of the malar bone and masseter muscle, 
from the surface of the superior maxillary bone joining the orbicularis oris; and its 
fibres extend to the mandible and orbicularis oris. 
The distorted condition of the incisors and jaws in the specimen of Aye-Aye dissected 
by us interfered with the natural condition of the parts in the neighbourhood of the 
mouth. 
ExTERNAL PreryGom.—This arises from the upper surface of the maxilla and the outer 
surface of the palatine bone beneath the orbit. It is inserted into the neck of the 
mandible beneath the condyle. 
Identical in the Galagos (PI. V. figs. 17 & 18, E.pt). In Tarsius* it is said to spring 
in the orbit from the os ethmoideum near the optic foramen. 
InTeRNAL PreryGorp.—This springs from the pterygoid fossa and the outer surface of 
the external pterygoid process, and is inserted into the inner side of the angle of the 
mandible. 
That of Galago crassicaudatus is figured by us in Pl. V. figs. 17 & 18, L.pt. 
In Tursius* this is larger than the external pterygoid ; it arises from the space between 
the two ascending branches of the pterygoid, and contains a strong internal tendon. 
c. Hyoidean and Inframandibular Regions. 
STERNO-CLEIDO-MASTOID.—This muscle is largely developed, and arises by a strong 
tendon from the manubrium, and by muscle from the inner third of the clavicle. As it 
passes forwards and upwards, the clavicular portion becomes covered by the sternal part’. 
The two portions are inserted into the skull behind the meatus auditorius externus. 
Cuvier, in his ‘ Planches de Myologie,’ pl. 68. fig. 1, letters a and b, quite agrees with 
the appearances we found, except that the sterno-mastoid (4) seems to consist of two 
parts, 7... to be longitudinally divided. In the list of muscles in the text, however, 
a and a! are described as indicating the trapezius (dorso-sus-acromien); and at pl. 69. 
fig. 1, a large broad muscle, marked a and a', is represented as passing downwards and 
backwards from the neck and occiput to the clavicle. We, however, have found no 
such muscle apart from cutaneous fibres, though several specimens were examined by 
us to ascertain the correctness of the delineation. 
In Galago crassicaudatus (Pl. IIL. fig. 5, St.m, and Cl.m, and Pl. II. fig. 3, S#.m) and 
in G. garnettii it is tolerably strong, and there is only a moderate division into two 
parts. In G. allenii, on the other hand, it is rather feebly developed. In G. peli® the 
‘ Van Campen, op. cit. p. 23. * Loe. cit. p. 32. % Loe. cit. p. 33. 
* Loe. cit. p. 33, tab. 5. fig. 14. ° Meckel, Anat. Comp. vol. vi. p. 169. ® Kingma, l. ¢. p. 21. 
