2 



Mr. J. Wood on Varieties of Muscles. [June 17, 



in his paper read before the Royal Society in 1864 ; he has found it 

 in 6 out of 202 subjects. In the present paper the author gives an 

 abstract of the observations of the older and modern anatomists re- 

 ferring to this muscle in the human subject under various names, and 

 enters at length into its homologies in the Mammalia, as described by 

 writers under its synonyms, — the levator scapula major vel anterior (Dou- 

 glass), omo- ou acromio-tracMlien (Cuvier and Meckel), acromio-basilar 

 (Vicq d'Azyr), basio-humeralis (Kr&nse) , Kopf-Arm-Muskel (Peyer), clavio- 

 trachelien (Church), transverso-scapulaire (Strauss-Diirckheim), omo- 

 atlanticus (Haughton), and cervico -humeral (Humphry), — illustrating 

 them by drawings from his own dissections. He enters more fully into 

 the discussion of the apparently anomalous composition of the muscle in 

 the Rabbit, gives reasons and comparative illustrations from the Fallow- 

 deer and Ass for considering the seeming doubling of the muscle to result 

 from a peculiar development of the cleido-mastoid in apparent conjunction 

 with it, and considers that the muscle which has gone under the last name 

 in the Rabbit to be really a development of the cleido- occipital. 



The cleido-occipitalhe described in his paper published in the Proceedings 

 of the Royal Society in June 1866 ; and he has found it since that time in 

 37 out of 102 subjects. In the present paper he quotes briefly the various 

 anatomists who have described it as part of the sterno-cleido-mastoid or 

 trapezius, and connects it homologically with the muscles which have 

 been described in the claviculate mammalia as a second cleido-mastoid, 

 and in the semiclaviculate as the trapezius clavicularis (" portion cervi- 

 cale") of that muscle, giving illustrations of its gradual or transitional 

 forms of development from specimens that have come under his own ob- 

 servation, or which have been gathered from the writings of others, as far 

 as to the formation of the compound cephalo-humeral or levator humeri 

 muscle of the Rodents and Carnivora. 



The stemo-scapular muscle was first described as a variety in the human 

 subject by the author in his paper published in the ' Proceedings ' in 1865 ; 

 it had been previously described by various anatomists and by himself as a 

 double subclavius, with an insertion into the scapula. In the present paper 

 he briefly quotes these authorities, and shows the various developments of 

 the muscle in animals. In connexion with it he describes a scapulo- 

 clavicular variety (first observed by him as a human variety in 1865), and 

 compares it with the human abnormalities described by authors as varieties 

 of the omo-hyoid. It is described by Cuvier as the " scapulo-clavien"" in 

 the Rat-mole of the Cape and in the Didelphis marsupialis, and has been 

 found by the author in the Rabbit, Guineapig, Squirrel, and Norway Rat. 



He also describes the specimens he has found of the sterno-clavicular 

 muscle, mentions the observers who have before seen it and recognized its 

 homologies, and gives illustrations of its formation in the Rabbit, Guinea- 

 pig, and other animals. 



The supra-costal muscle was first discovered and described and figured 



