318 MESSRS. B. C. A. WINULE AND F. G. PARSONS ON [Mar. 7, 



from the anterior inferior border and from the inferior angle of 

 the malar, and is inserted into the lower border of the mandible 

 from the angle to midway between the angle and the symphysis. 

 The deep layer comes from the lower part of the posterior border 

 of the malar and is inserted into the outer surface of the mandi- 

 bular ramus. In his elaborate account of the muscles of the face 

 in Myrmecophaga, Owen does not mention any bilamination of the 

 masseter. In Dasypus (22) the muscle is distinctly bilaminar. 

 The same condition obtains also in Chlamydophorus (27, 28), 

 •where, according to Hyrtl, it is intersected by tendons. In Manis 

 (29, 30) the masseter is thin and unilaminar and arises from 

 a fibrous zygoma. We have no records of its condition in 

 Orycteropus. 



Temporal, Buccinator, and Pterycjoidei show no points of special 

 interest. 



Digastric. — In the Bradypodidce this muscle reaches from the 

 paramastoid process to the middle third of the body of the 

 mandible. In 1, 5, and 6 it is described as possessing a slight 

 tendinous intersection opposite the hyoid bone, from the inner side 

 of which intersection is given off a fibrous arcade similar to 

 that met with amongst the Sciuridte. In 3 no tendinous intei*- 

 section was noticed. Choloepus (9) has a tendinous intersection, 

 though none was noticed by MacaUster in his specimen. We 

 have no records of the digastric in any of the MyrmecophagidcB. 

 Among the Dasypodidce the digastric is described as monogastric 

 by MacaUster, who states that it is attached below the mandible 

 in Dasypus and Tatusia. In our specimen of Dasypxis, and in a 

 second which we specially examined with reference to this point, 

 the muscle was absent, but it is figured by Cuvier and Laurillard (24) 

 as arising by tendon and inserted by fleshy fibres. In Chlamy- 

 dophorus, MacaUster found a very small digastric passing from the 

 bulla tympani to the mandible, but Hyrtl found none in his 

 specimen of the same animal. In the llanidce the digastric is 

 inserted into the lower jaw as far as halfway to the symphysis ; 

 it possesses no central tendon (29). In the Orycteropodid(B 

 (36, 37) the muscle has the same arrangement. 



Mylo-hyoid. — This muscle is always well marked in the Eden- 

 tates, being especially large in Myrmecophaga, Tamandtia, and 

 Manis, in all of which animals the posterior fibres curve round the 

 sterno-glossi and the part of the tongue into which these are 

 inserted, forming a narrow tunnel or sheath in which they are 

 enclosed. 



Sterno-maxillaris, Byoid, and Thyroid. — The first of these 

 muscles is absent in the Bradypodidce. In Bradypus (1, 5) the 

 latter two are fused as far as the caudal edge of the larynx, at 

 which point a slip is delaminated from the mesial and ventral part 

 of the muscle and continued to the hyoid bone, the greater part 

 of the muscle passing to the thyroid cartilage. In Cholapus (10) 

 the two muscles have practically the human attachments. In the 

 Myruiecopjhagidce the sterno-maxillaris is present as a superficial 



