DR. J. MUEIE OX THE FORM AND STRUCTURE OP THE MANATEE. 147 



borum in every respect save size. The last superficial muscle ought possibly to be 

 included among the dorsal series. It is evidently the homologue of a small muscle 

 met with by Mivart and me in Galago crassicaudatus. In that animal it lies outside the 

 origin of the levator caudse externus, and comes from the lumbo-iliac fascia, and is 

 inserted by tendons on the side of the root of the tail above the sacro-coccygeus. 

 Doubtfully named by us ', I here denominate it in the Manatee lumbo-caudalis. I do 

 not recognize in Manatus any division of the infralumbar muscles agreeing with psoas 

 and iliacus. If these are present they are indivisibly fused with the infra and sacro- 

 coccygeus, and, besides, can have no limb-attacliment. 



The great inferior loin- and tail-muscle of Cetacea Rapp regarded as a psoas ; and he 

 describes as costalis one of the outer dorso-caudal muscles. Meckel and others adopt 

 a similar interpretation ; but Stannius, in his myology of Lelpliinus, Phocmm, and the 

 American Manatee, opposes Rapp. He names in the former a sacro-lumbalis superior 

 and sacro-lumbalis inferior, a longissimus superior and inferior, a transversarius superior 

 and inferior, a caudalis inferior, besides intertransversarii. He regards the Sirenian 

 caudal muscles as nearly equivalent, more particularly laying stress on the so-called 

 transverse muscles, these being below, as I presume, ray sacro- and infra-coccygeus, and 

 above the levatores. 



Of the deep muscles of the ventral surface of the neck, the longus colli, which is 

 altogether broad and flat, may be reckoned as consisting of three triangular parts. 

 These, however, are not very readily separable into distinct portions ; but the difiference 

 in direction of the fibres and attachments sufficiently define them. The first or pos- 

 terior portion, homologous with the inferior oblique portion of higher mammals, covers 

 the under surface of the transverse processes of the last two (fifth and sixth) cervicals 

 and roots of the first two ribs. The second anterior or superior oblique slip of fleshy 

 fibres arises widely from the ventral surface of the atlas, and is inserted narrowly and 

 superficially tendinous into the rudimentary transverse process of the fifth cervical 

 vertebra. The third inner and largest moiety of the longus colli has origin apically 

 from the middle of the body of the atlas, and, widening on the surface of the neck, is 

 attached to the inferior surfaces of the bodies of the succeeding cervical vertebra. 



The rectus anticus minor is seen on the outside of the rectus anticus major, and is 

 fairly developed as a fleshy band whose origin is behind and beneath it cranially. It is 

 inserted on the outer and imder surface of the atlas. 



Considering the diminished extent of neck, the rectus anticus major is remarkably 

 large and comparatively long. As in the Galagos and other aberrant Lemurs, it extends 

 from the basilar process of the skull backwards to the bodies of the anterior dorsal 

 vertebrae. In the thorax it ends in twg long, flattened, strong tendons — one to the 



' In Trans. Zool. Soe. vol. vii. pi. 2. fig. 3, lettered Itxd, it is regarded as perhaps au anterior prolonga- 

 tion of the intertransversarii caudse ; but in the tail-dissection, pi. G. fig. 25, where full)- exposed, we leave it 

 unlettered. 



