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MR. ST. GEORGE MIVART ON THE 



[June 27, 



extend down to the junction of the vertebral ribs with the sternal 

 ones. 



FiK. 3. 



Subvertebral nwsclos of right side. 

 Q. L. Quaclratus himborum. E. C. Retrahentes costarum. 



Retrahentes cosfarum. A very remarkable muscular layer* 

 (fig. 3, R. C), which is tendinous at its insertion and at the posterior 

 part of its origin, but muscular elsewhere. It has a certain reseni- 

 i)lance to the diaphragm, as it is internal to all the other body- 

 muscles. 



It arises from the sides of the ventral surfaces of the bodies of nine 

 vertebrae, beginning with the first dorsal. The muscular fibres pro- 

 ceed forwards and ventrad, and are inserted into the ribs of the seventh 

 and eighth cervical vertebrae, and into the seven following ribs. The 

 insertion of the aponeurosis is close to the origin of the fascia of the 

 transversalisf. 



Pyramidalis (fig. 14, Py.). This muscle is largely developed, 

 and is placed beneath the rectus. It arises from the ligamentous 

 arch extending back from the spine of the pubis ; and its fibres ad- 



* Tlie in. retrahcnfes costarum of Stannius (Joe. cif. p. 1(>3). 

 t As Stannius roniarks {Joe. cif. note 4 to ]). 103). 



