1899.] ' a?HE MYOLOGY OP THE EDENTATA. 319 



delamination from the sterno-hyoid {M. jubata, Owen, XV.). In 

 Tamandua and Cyclothurus it rises from the manubrium and is 

 inserted into the mandible near the symphysis. In the Dany- 

 podidce the sterno-maxillaris is also present in Dasypus (22), 

 Tatusia (25), and Cldaniydopliorus (27, 28). In the Manidce no 

 sterno-maxillaris was noticed nor is any recorded in Orycteropus. 

 The only animal in which a tendinous intersection was noticed 

 was Tamandua (14), in which the condition existed in the sterno- 

 maxillaris. 



Sterno-glossus. — This muscle has so far only been recorded in 

 Myrmecophaga, Tamandua, and Manis. Whether it is present in 

 Cyclothurus we are unable to state. It rises from the xiphi- 

 sternum and the last one or two true ribs and passes forward at 

 first deep to the sternum and costal cai^tilages, and is subsequently 

 eusheathed, as has already been mentioned, in fibres derived from 

 the mylo-hyoid, to be inserted into the tongue. In Myrmecophaga 

 Owen points out that it is intersected in its thoracic portion by 

 linese transversse. 



Styloid Muscles. — The stylo-hyoid, glossus, and pharygneus 

 seem to be generally present, and of these the stylo-glossus appears 

 to be always the best developed. The stylo-pharyngeus is usually 

 small, and the stylo-hyoid is sometimes absent. 



Omo-hyoid. — In no Edentate have we ever seen this muscle, 

 nor is it specifically described by any author, though it is stated 

 in one paper that Cuvier noted it in Myrmecophaga, a reference 

 which we have been unable to trace. 



Sterno-cleido-mastoid. — In the Bradypodidce, Bradypus (1,3,4) 

 is remarkable for having the two parts closely united, whilst in 

 Cholcepus they are distinct. In Bradypus the single muscle rises 

 from the manubrium and the fascia external to it and may (3) get 

 a slight origin from the rudimentary clavicle. It is inserted into 

 the paramastoid and paroccipital region of the skull and has the 

 spinal accessory nerve on its deep surface. In Cholcepus both 

 sterno- and cleido-mastoids are present, the latter coming from 

 the middle third of the clavicle, and the spinal accessory nerve 

 passes between them. The cleido- mastoid muscle when it is 

 present is, as in most mammals, inserted deep to the sterno- 

 mastoid. In the Myrmecophagida, Myrmecophaga and Tamandua 

 have only a sterno-mastoid, but Cyclothurus, in which the clavicle 

 is well developed, has both sterno- and cleido-mastoids (17, 21). 

 In one specimen of this animal (19) there are described distinct 

 sterno-mastoid, cleido-occipital, and cleido-mastoid, the latter 

 lying deep to the cleido-occipital. It is to be regretted that the 

 relation of the spinal accessory nerve to these three muscles is 

 not recorded. In the Dasypodida?, Dasypus (22, 23, 24), Tatusia 

 (25, 26), and Chlamydophorus (27) have separate sterno- and 

 cleido-mastoids. In the last-mentioned animal, Hyrtl (28) 

 mentions that the sterno-mastoids of opposite sides are fused 

 in the neck. In Manis (29) the cleido-mastoid is absent. In 

 Orycteropus (35, 36, 37) both sterno- and cleido-mastoids are 



