MUSCULAR ABNORMALITY IN THE CAT. 341 



a failure to fuse or only partial fusion, where normally complete 

 fusion occurs. 



The abnormality here under consideration has suggested to me 



the view that normally in man the omotransversarius element is 



fused completely with the cleidomastoid portion of the M. sternoclei- 



domastoideits. This view would make the sternocleidomastoid a 



complex of six elements, as shown in the following scheme : 



f Sternomastoideus superficialis ^ 

 Sterno-occipitalis L Superficial. 



Cleido-occipitalis 

 M. sternocleidomastoideus (Man) -j 



Sternomastoideus profundus - 

 Cleidomastoideus > Deep. 1 



^ Omotransversarius 



The evidence for this view comes from two sources. In the 

 first place, the occurrence in anomalous cases in man of a sepa- 

 rate M. omotransversarius makes it extremely probable that this 

 element is generally present in man, but in normal cadavers is 

 completely fused with some other muscle. In the second place, 

 the anomalous case in the cat just described shows that in a form 

 lower than man it is possible for a partial fusion of the cleido- 

 mastoid and omotransversarius muscles to occur as a variation. 

 This makes it seem probable that the muscle complex with which 

 this omotransversarius element in man normally fuses is the ster- 

 nocleidomastoid. 



SUMMARY. 



1. A case of insertion of a portion of the M. latissimus dorsi on 

 the M. pectoantibrachialis is described. 



2. A case of partial union of the Mm. cleidomastoideus and 

 levator scapulae ventralis (or omotransversarius) is described. 



3. The view is advanced that the human sternocleidomastoid 

 muscle contains an omotransversarius element. This element is 

 normally completely fused with the deep portion of the sterno- 

 cleidomastoid, but, in abnormal cases, it may fail to fuse com- 

 pletely and consequently then appears as a separate muscle. 



