1899.] THE MYOLOGY Of THE EDENTATA. 321 



meut of a portion of the rectus ventralis. We have, however, very 

 carefully examined the question and have come to the conclusiou, 

 from the facts that (i.) it so often continues the direction of the 

 scaleui and (ii.) is occasionally connected to them by direct fibres, 

 that the muscle should be looked upon as a caudad extension of 

 scalenus longus and that its presence is correlated with the fact, 

 already insisted upou, that the last-named muscle has a very- 

 limited attachment in the costal region. In the BradypocUdce the 

 muscle was noticed in five specimens of Bradypus (1, 3, 4, 5, 6) ; 

 it was attached in all to the first rib anteriorly, but its posterior 

 connections were various. In Choloepus (10) it passed from the 

 first and second ribs to the eighth and ninth. Amongst the 

 Myrmecophagidce, we have no record of its occurrence in Myrme- 

 cophaga itself, but in Tamandua (14, 16) it is well marked and 

 passes from the first to the seventh and eighth ribs ; it was also 

 present in four specimens of Cydotlmrus (17, 19, 20, 21). In 

 the Basypodidce the muscle, for some reason not appai^ent to us 

 shifts its anterior attachment nearer to the mid-ventral line. Thus 

 in Dasypus (22), as we have already mentioned, it is attached deep 

 to the rectus ventralis, whilst in Tatusia (25) its anterior attach- 

 ment is to the manubrium sterni. In Ghlamydopliorus (27) the 

 muscle is very slender and feeble and is attached to the first rib. 

 In another specimen of the same animal (28) Hyrtl does not 

 allude to the muscle. Amongst the Manidce the muscle was 

 found passing from the 1st to the 3rd, 4th, 5th, 6th, and 7th ribs in 

 Manis (29). Its presence is not recorded in any of the descriptions 

 of the Oryderopodidce, nor do Cuvier and Laurillard figure it in their 

 plates of the myology of this animal (37). 



Recti capitis dorsales. — There does not seem to be any delami- 

 nation, producing a r. c. d. medius, as is the case in "so many 

 mammals. We find only records of r. c. d. superficialis et profundus 

 (r. c. posticus major and minor), as in Man. 



Splenius capitis et colli. — These muscles are subject to a good 

 deal of variation in the Edentata and especially amongst the 

 Bradypodidce. In Bradypus, a form possessing nine cervical 

 vertebrae, we are not surprised to find the colli very large and the 

 capitis either very small (1, 4, 6) or absent altogether (3). In one 

 specimen (3) there were two splenii colli, the anterior arising from 

 the spines of the 3rd, 4th, 5th, and 6th cervical vertebrte, while the 

 posterior came from five spines behind these. In Choloepus (10), 

 a form in which the number of cervical vertebrae is liable to 

 reduction, the splenius capitis was large and rose from all the 

 cervical spines or the ligamentum nuchae dorsal to them. The 

 splenius colli was absent. Amongst the Myrmecophagidce there 

 was no splenius colli in Tamandua (14) or C'yclothurus (21), In 

 another specimen of the first-named auimal (16) it went to the 

 atlas only. Amongst the Basyjoodidce there was no splenius colli 

 in Dasypus (22, 24), Tatusia (25), or Chlamydoplio'nis (27). In 

 Manis (29) there is also no splenius colli, nor have we anv record 

 of the muscle in Onjcteropus. We may sum up the description of 



