MUSCULAR SYSTEM. J G3 



obliqui, (A. /,) and the transversales abdominis, (A. ,) are 

 here of considerable extent, passing forwards around the 

 abdominal cavity, beneath the sternum and the ribs, and 

 assisting in respiration and in the discharge of all the natural 

 excretions. Behind the diaphragmatic bands (B. /, m,) are 

 the posterior insertions of the large retrahentes capitis et colli 

 (B. k,) which extend forwards along the back part of the 

 neck (B.,/,) to retract the head and neck under the ribs. As 

 the ribs are immoveable, the motions of inspiration are ef- 

 fected chiefly by the os hyoides, as in amphibia where the 

 ribs are almost or completely wanting, and most of the mus- 

 cles connected with that bone are large and distinct, like the 

 parts of the os hyoides itself. The genio-hyoideus (B./.) 

 forms a broad muscle extending forwards to the lower jaw, 

 and the omo-hyoideus, (B. i y ) continues backwards as a broad 

 muscular expansion, covering the lower part of the neck. 

 The hyo-glossus, hyo-maxillaris, genio-glossus, are also here 

 distinct, and the stemo-mastoideus, the digrasticus maxilla, 

 trachelo-mastoideus, (B. /*,) and most of the muscles which 

 move the head, are well marked in these long-necked ani- 

 mals. The large pectoral muscles have an extensive attach- 

 ment to the interior of the sternum. Two broad muscles 

 proceeding, in different directions, from the sternum to the 

 pubic bones, and constituting the attrahens and retrahens 

 pelvim on each side, appear to be the analogues of the recti 

 abdominis. The serratus magnus, deltoides, sub- and super - 

 scapularis, triceps, (A. <?,) and biceps (B. y } ) brachii, and most 

 of the succeeding muscles of the arm and hand are powerful, 

 especially in the land tortoises, where the arms are fixed in 

 a state of pronation, the best suited to support the weight of 

 the body. The flexor sublimis (A. r } ) forms a strong mus- 

 cular band on the outside of the fore-arm. The broad ten- 

 dons of the extensor communis digitorum manus, (A. s,) cover 

 the back part of the carpus, and on the upper part of the 

 fingers are the five strong extensores breves digitorum manus, 

 (A. /.) The brachialis internus (B. #,) the palmaris, (B. z.) 

 the flexor profundus, (B. 2,) and most of the flexor muscles 

 of these extremities are strong, both for support and for 

 digging. In the long, fin-like arms of the turtles, the mus- 

 cles of the shoulders are those chiefly developed, while the 

 muscles of the fore-arm and hand are very feeble, as in ceta- 



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