THE MYOLOGY OF THE HEDGEOG. 445 



It is, in fact, tlie cliief agent in coOing tlae body up, and 

 keejDing it so coiled. 



Numerous muscular bundles take a radiating direction 

 on tbe dorsal aspect of the body, and antagonize tbe orbi- 

 cularis: 1. A pair of slender occipito-frontales arise from the 

 occipital crest, and are inserted into the integument over 

 the frontal and nasal bones. 2. A pair of occipito-orbiculares 

 arise from the same crest, and pass into the anterior part 

 of the orbicularis. 3. A pair of broader cervico-orbiculares 

 arise from the fascia of the neck, and pass to the dorsal 

 part of the anterior fourth of the orbicularis. 4. Slender 

 dorso-orbiculares arise close to the hinder ends of the tra- 

 pezii and spread out above the foregoing. 5. Two stout 

 muscles, coccygeo-orbiculares, arise from the middle caudal 

 Yertebree, and after receiving fibres from the ventral region, 

 end in the dorsal margins of the orbicularis. 6. Two 

 muscles attached to the pinnae of the ears {auriculo-orbicu- 

 lares) pass backwards to the orbicularis on each side. 



On the ventral aspect are certain muscles which assist 

 the orbicularis : 1. Two broad muscles {sterno-faciales) arise 

 in the middle line, over the anterior part of the sternum, 

 and pass outwards and forwards to the sides of the lower 

 jaw and the integument of the face and ears. Muscular 

 slips from these are sent up over each shoulder to the 

 orbicularis. 2. A humero-abdominalis arises from each 

 humerus beneath the insertion of the pectoralis major, and, 

 passing backwards over the sides of the abdomen, these 

 become connected with the ventral edges of the orbicularis. 

 The external fibres of these muscles are continued round the 

 ischial region to the coccygeo-orbicularis ; the internal fibres 

 pass to the prepuce, and over the middle line of the ab- 

 domen, in front of it. 3. A Immero-dorsalis arises from the 

 humerus close to the foregoing, and passing upwards and 

 backwards through the axilla, spreads oiit in the mid- 

 dorsal integument and the orbicularis. 



The contraction of all these muscles must tend to bring 

 together the edges of the integumentary bag, and to tuck 

 the head, tail, and limbs into it. 



