REPORT ON THE SEALS. 221 



over the ventral surface of the 15th rib the outer third of the muscle terminates, over the 14th 

 rib the half of the remaining fibres, and over the 13th the rest. 



Lucae makes no distinction between the true subcostals and the scalenus lumborum, but 

 describes both under the name subcostalis vertebralis. The drawing by Meyer shows the scalenus 

 lumborum terminating at the last rib, but in Phoca and Arctoccplialus it is prolonged forwards to 

 the under surface of the third last rib. In Otaria and Trichech/as it has not been figured or 

 described. 



The Subcostales in Phoca vitulina usually commence at the 7th or 8 th intercostal space ; there 

 are six or seven of them, and they lie next the vertebral column. Each arises from the ventral 

 surface of the rib joint, from the posterior part of the vertebra in front of the one with which the 

 rib articulates, and from the rib close to the joint. The fibres pass over the rib in front of their 

 origin, and are inserted into the posterior border of the next. The last two muscles have the 

 scalenus lumborum along their outer borders. 



In Arctocephcdus there are twelve of these ; all arise from the posterior part of the body of a 

 dorsal vertebra, and are inserted as in Phoca vitulina, having a rib intervening between the origin 

 and insertion. The muscles are much narrower than in Phoca, and commence in the 3rd intercostal 

 space. 



In Otaria and Trichcchus they are not mentioned. 



The Lcvatorcs costarum both in Phoca vitulina and in Arctocephalus are a series of small triangular 

 muscles, with their bases directed away from the spinal column. There are fifteen on each side of 

 the back ; they arise from the dorsal tips of the dorsal divisions of the transverse processes of the 7th 

 cervical and the anterior ten dorsal vertebras, and from the under surfaces of the anapophyses 

 of the 11th, 12th, 13th, and 14th dorsal vertebrae. The anterior muscles are small and narrow, the 

 posterior short and broad, and the intermediate much the longest. They are inserted into the dorsal 

 surface of the rib below the originating point, then into the anterior border of the same rib for a 

 little distance beyond this. In the large Phoca vitulina I found only fourteen. 



The Triangularis stcrni is Lucae's subcostalis sternalis; in Phoca vitulina it lies upon the inner 

 side of the sternum and covers the internal mammary artery. It arises from the side of the 

 manubrium reaching as far forwards as the anterior border of the 4th rib, from the junction of the 

 cartilages with the sternum from the 4th to the 10th ribs, and from the anterior half of the side of 

 the ensiform cartilage. The muscle is divided into a number of serrations; in this dissection there 

 were nine on each side, six arising from the manubrium and three from the ensiform cartilage ; those 

 from the manubrium were much larger than those from the ensiform. Each serration frorn the 

 manubrium extended from the posterior border of one rib to the back of the next behind. The 

 posterior fibres are not so obliquely directed forwards and outwards as the rest ; the anterior 

 fibres are most oblique. The last serration from the ensiform cartilage crosses the cartilage of the 

 11th rib, and is inserted into the lower border of the cartilage of the 10th rib; the penultinate 

 crosses the cartilages of the 10th and 11th ribs, and is inserted into the lower and inner surface of 

 the cartilage of the 9th rib ; the last but two crosses the cartilages of the 11th, 10th, and 9th ribs, 

 and is inserted into the lower border and inner surface of the 8th cartilage. The other serrations 

 are inserted into the under and inner surfaces of the cartilages of the 2nd to the 7th ribs, each 

 serration crossing two ribs before reaching its' attachment. 



In Arctocephalus it arises from the anterior half of the sternum by fibres, and from the ventral 



