the Wombat and Tasmanian Devil. . 159 



muscle is known (calling it brachio-lateralis)-, regards it as an 

 intermediate piece of the great superficial external muscular 

 sheet between the pectoralis major and the latissimus dorsi — 

 a conclusion which, I think, is warranted from its position. 

 It is most powerfully developed in swimming animals, such as 

 tlie seal and the otter, in wliich its action is very definite and 

 important. 



There was no lateral rectus thoracicus in any of the marsu- 

 pials which I have dissected. The transversi thoracis, an- 

 terior and posterior, are weakly developed in Sarcoj)hUus] 

 the latter is distinct, though small, in the Wombat ; and the 

 former is present and well marked in Macropus giganteus 

 and Bennettu. 



The deltoid of theWombat is divided into two parts : one of 

 these (the clavicular) has been mentioned already in connexion 

 with the trapezius. The scapular deltoid arises from the 

 acromion process and scapular spine, and is attached to the 

 deltoid crest on the humerus separate from the preceding ; 

 this crest is prominently marked, although the deltoid is not 

 very large. 



In the Tasmanian Devil the acromial deltoid is separate 

 from the scapular, and the latter is a long narrow muscular 

 band. There is no clavicular deltoid separate from the outer 

 fibres of the acromial portion. An undivided clavicular and 

 scapular deltoid occurs in the Giant Kangaroo and in Ma- 

 cropus Bennettii^ more extensive in origin in the former than 

 in the latter. It is similarly attached in the Phalanger and 

 Virginian Opossum. In Perameles Professor Owen describes 

 an accessory slip arising from the middle of the inferior costa 

 of the scapula below the infraspinatus, and inserted into the 

 upper part of the deltoid-crest of the humerus. I did not see 

 this interesting aberrant accessory fasciculus in any of the 

 other marsupials examined. 



The supraspinatus is larger than the infraspinatus in the 

 Wombat, the Phalanger, Perameles^ Sarcophilus, and the 

 Opossum ; in the Giant Kangaroo they are about equal, while 

 in Bennett's Kangaroo the infraspinatus is the larger. There 

 are no points of importance relative to these muscles ; they 

 are attached to the capsule of the shoulder, but none of these 

 capsular muscles perforate it. The supraspinatus is often 

 larger in other animals than the infraspinatus, as in the Lion, 

 Agouti, Guinea-pig, Kabbit, Hare, liat, Llama, &c. 



The teres minor is not distinct from the infraspinatus in the 

 Wombat or 8arcoj'>/nIus, but a distinct fascial band takes its 

 place ; in the Wallaby it is present and separate ; but in 

 Macropus giganteus, Phalangista vulpiyia, Perameles lagotis, 



