1896.] MYOLOGY OF KOHENXa. 165 



paroccipital process, by fleshy fibres. The sterno-mastoid has the 

 usual, origin and is inserted by tendon into the base of the par- 

 occipital process in front of the last muscle ; it is the larger muscle 

 of the two. In Gricetomys the cleido-mastoid is not covered by 

 the trapezius at its origin, it is, however, overlapped by the sterno- 

 mastoid at its insertion. In the Qerbille the two muscles are con- 

 tinuous at their origin, the cleido-mastoid being the larger and 

 rising from the inner half of the clavicle. RMzomys resembles 

 Cricetus, Myo.vus, and the Marines in the origin of the cleido- 

 mastoid being overlapped by the trapezius, and Cricetotnys in the 

 insertion being overlapped by the sterno-mastoid. In Hydi-omys ' 

 the cleido-mastoid is the smaller muscle and is overlapped at its 

 insertion by the sterno-mastoid. In Georychus and Bathyeryus 

 the cleido-mastoid is not overlapped by the trsipezius ; in the latter 

 the two muscles tend to fuse as in the Gerbille, but to a greater 

 extent ; at their insertion they are completely fused and are attached 

 by a narrow tendon to the base of the paroccipital process. 



Sterno-hyoid and thyroid. — In most cases these muscles have the 

 human attachments. In Bathyeryus, however, the sterno-hyoid 

 ^ misses the hyoid bone and continues on to the symphysis menti, 

 in this respect somewhat resembling the arrangement; found in 

 Myopotamus'. In Hydromys the arrangement seems idejitical 

 with that of Myopotamus '. 



Omo-hyoid. — As in the Sciuromorpha the omo-hyoid is always 

 present in the Myomorpha ; it has the same attachments, uever, as 

 far as I have seen, being attached to the clavicle. There is no 

 central tendon. In Bathyeryus the muscle is not attached to the 

 hyoid bone, but is continued forwards with the sterno-hyoid to the 

 symphysis menti. 



Levator Glaviculce. (Acromio-irachelian). — In all the animals 

 examined this muscle rose from the anterior arch and transverse 

 process of the atlas. Its usual insertion is into the acrnmial pro- 

 cess, but sometimes it extends to the spine of the scapula. This 

 description applies also to Hydromys '. In Bathyergits the muscle 

 is very large and extends from the acromion on to the outer half 

 of the clavicle at its insertiou, in this respect; resembling the 

 Dipodido). 



liectvs Gapitis Anticus Major and Minor and Lonyu-i Golli. — 

 These muscles have the Hystricomorphine attachments. 



Scalene Muscles. — A scalenus anticus, that is a muscle passing 

 to the first rib in front of the subclavian artery and brachial plexus, 

 was only seen in the following animals — Qerbillus, Georychus, and 

 Bathyeryus. In these it resembled the same muscle among the 

 Hystricomorpha, in rising from the basioccipital bone. The sca- 

 lenus medius and posticus of human anatomy are represented by 

 one mass, which rises from the transverse processes of all the cer- 

 vical vertebrae, passes behind the brachial plexus, and is inserted into 



> P. Z. S. 18S7, p. 55. 

 = P. Z. S. 1894. p. 256. 

 ' P. Z. S. 1S87, p. 55. 



