1899.J THE MYOLOGX OF THE EDEIfTATA. 1007 



three lumbricales are usually found, while in the OnjcteropodidoB 

 (35, 36) there are four. 



Musculi breves pedis. — The abductores hallucis et minimi digiti 

 are of course absent in the Bradijpodidce, but in all the other 

 families thej are present. In the Oryeteropodidce, however, the 

 abductor hallucis is replaced by fibrous tissue. The flexor brevis 

 hallucis is present in all Edentates escept the Bradypodidce. In the 

 Oryderopodidce (35, 36) its absence is noted, but Humphry (36) 

 states that it is rejilaced by fibrous tissue. It is present in all 

 other Edentata, including OyclotJiurus. The abductor minimi 

 digiti is present in the Myrmecophagidce, Dasypodidce, Manidce, and 

 Orycteropodidce ; it usually rises from the base of the fifth meta- 

 tarsal bone, instead of from the calcaneum as in most mammals. 

 The superficial layer of deep muscles, ;'. e. those which lie superficial 

 to the deep branch of the external plantar nerve and are usually 

 called adductors, are wanting in the Bradypodidce and Manidce. 

 In the following animals adductores hallucis et minimi digiti were 

 found : — CyclotJmrus (20), Dasypus (22), Tatusia (25), and Oryc- 

 teropus (35, 36). Tamaivdua (14) in addition had an adductor 

 indicis. The interossei are usually present as paired flexores 

 breves, but in the Dasypodidce and Manidce a differentiation into 

 dorsal and plantar groups is noticed; their exact arrangement, 

 however, differs in different specimens of the same animal. 



Abdominal Muscles. 



Serratus dorsalis (S. posticus'). — The two portions of this muscle, 

 thoracis and lumbalis, seem to be but little developed in the Eden- 

 tata, and this statement particularly applies to the former of the 

 two. Amongst the Bradypodidce the muscle is represented only by 

 a fibrous sheet in Bradypus (1), whilst in CJioloepus (10) the thoracic 

 portion is absent, but the lumbar, attached to the lower ribs, is 

 present. Amongst the Myrmecophagidce a fibrous representative of 

 the muscle was found in Tamandua (14) ; it is not figured, however, 

 in Cuvier and Laurillard's plate of the same species (16). Dasypus 

 amongst the Dasypodidce does not seem usually to possess any 

 representative of this muscle, for none was fouud in (22) ; Galton 

 (23) does not mention one, nor is any figured by Cuvier and 

 Laurillard (24). Indeed we could have asserted that there is none 

 but for the fact that Macalister (VI.) seems to have found a repre- 

 sentative of the muscle in one case. In Tatusia (25) a very feeble 

 thoracis was found, and a lumbalis attached to the lower four 

 ribs. Chlamydophorus (27, 2S) had a similarly arranged lumbalis 

 but no thoracis. In Manis (29) a fibrous representative was alone 

 found. In Orycteropnis (37) Cuvier and Laurillard figure a 

 continuous sheet extending from the third to the tenth dorsal 

 vertebra which appears to be an unusually well-developed 

 thoracis. 



Rectus ventralis. — This muscle in the majority of forms reaches 

 as high a point of attachment as the first rib, though sometimes 



65* 



