320 MESSES. B. C. A. -WINDLE AND F. G. PABSONS ON^ [Mar. 7, 



present, and the latter arises from the inner | or 3 of the 

 clavicle. 



Omo-trachelian. — This muscle is not a constant feature in 

 Edentate myology. When present, it arises, as is usually the case 

 amongst mammals, from the transverse process of the atlas, and is 

 inserted into the acromion process. In the Bradt/poclidre it was 

 present in Bradijpus (1, 3), being inserted in the latter specimen 

 into the upper angle of the scapula. In another specimen (5) its 

 existence is not mentioned, nor has it been noticed in ChoJcepus. 

 In the MijrmecopluKjidie the muscle was absent in Myrmecopluuja 

 (13), but present and well marked in Tamandua (16) and C'yclo- 

 thurus (18, 19). In the DasypodidcB the muscle was absent in 

 two specimens of Dasypus (22, 24) and no mention is made of its 

 presence in a third (23) ; Macalister, however, records its existence 

 in a specimen. In the Munidce the muscle is well marked, but 

 shifts its anterior attachment from the atlas to the mastoid region 

 of the skull (29, 30, 31, 32). 



Scaleni. — In no Edentate have we seen or met with any record 

 of a scalene muscle lying on the ventral aspect of the subclavian 

 vessels, so that it may be fairly definitely laid down that the 

 scalenus ventralis is a muscle totally wanting in this order. The 

 scalenus longus is attached to a very small number of ribs, another 

 characteristic feature of Edentate myology. The following table 

 gives a list of the attachments of longus and brevis in several 

 specimens : — 



Longus. Brevis. 



£radypus(l) 6, 7, 8, 9 C. \^. & rib i. 6, 7, 8, 9 C. V. & rib i. 



!> ("*) )1 " " " 



Cholcepus (10) 2, 3, 4, 5, 6 C. V. & ribs i., ii. 



Tamandua (14) 3, 4, 5, 6 C. V. & rib i. 4, 5, 6, 7 C. V. & rib i. 



Cyclothurus (17, 21) ... 4, 5, 6, 7 C. V. & rib i. 



Bast/pus (22) ribs iii., iv., v. ribs ii., iii., iv. 



Tatusia(25) ribs i., ii., iii. ribs i., ii. 



CUamydophorus (27). . . 2, 3, 4, 5, 6 0. V. & rib ii. 2, 3, 4, 5, 6 C. V. & rib i. 



Manis{2Q) 2,3,4, C. V. & ribs ii., iii., iv. 4,5, C.V. &ribi. 



Rectus thoracis lateralis. — This muscle is, so far as we know, 

 characteristic of the Edentates, as we have neither met with it nor 

 any description of it among other mammals, in the [course of our 

 researches. It continues the direction of the scalenus longus 

 caudalwards, being attached anteriorly to the first rib or pair of 

 ribs and posteriorly to some of the hinder ribs. Asa rule, the 

 muscle is external to the rectus ventralis, but when the two 

 overlap, as they did in our specimen of Dasypus (22), the rectus 

 ventralis is the more superficial of the two, a fact which shows 

 that the rectus thoracis lateralis cannot be regarded as a dis- 

 placed supra-costalis. Indeed, the fact that it is found in Choloejjus 

 (10) co-existing with the supra-costaUs is alone sufficient to prove 

 this. Macalister considers that this muscle is a lateral displace- 



