Wliicli iire now llie lioiuuIoj;icn l)et\veeii the iihtlumiiuil luu^icles 

 of Primales and tliose of lower Vcrlehmtes? Tliat tlie M. transv. 

 and the M. ohliq. int. of man are liomoloi;oii,s willi tlie honioiiyiiioiis 

 niiiseles of Urodela is obvious, on aoconnt of llie corresponding- 

 direction of tiie iibres and tlie corresponding direction of the inter- 

 costal nerve between liie two ninscles. Tiiere are iiowever different 

 views concerning the M. obliq. ext. Gegenbauk reckons this nmscle 

 together with the Muscnli intercostales exrerni to the layer of the 

 M. obliq. ext. prof, of Urodeles; in this case the M. obliq. ext. snperf. 

 of Urode'es conid be found back in the iMnsculi .seriati postici of 

 man. According to Eisi.kk ') the M. ol>li(|. exi. and iiic Musculi 

 serrati postici lielong to the la\ er of the M. obli(|. cxI. superliciaiis ; 

 the M. ol>li(i. ext. prof, of urodeles is to be fonnd back in tlie 

 Musculi intercostales extcrni and the "tiefe Zacken des lAl. obli(|. 

 ext. abdominis". By these Eisi.kk understands small itnndles of 

 nuiscles, which, as he conununicales, occur frefpiently under the 

 cranial origins of the M. obiicp ext. of man. They originate likewise 

 from the ribs, are separated liy some connective tissue from the 

 JM. oi)lii|. ext. lying superficially from (hem, lia\e an almost iians- 

 versal direction and lose themselves al last in the anterior lamella 

 of the sheath of the M. rectus. 



Tiie anatomy of the ventral Ininkmusciilulure of man Iiowever 

 cannot give us certainty with regard to the origin of the M. obliq. 

 ext. As. however, with other Primates between this muscle and the 

 M. obliij. int. a membrane occurs that can be conceived as the 

 remaining part of an abdominal muscle, the siimuion becomes 

 clearer. Superlicially from the M. obliq. int. we liiid lirst u muscle 

 reduced to a membrane and then a well (lcvelope<l muscle entirely 

 independent of each other ; it is thus without more obvious, that 

 the more superlicial one of these two layers must be homologous 

 with llie M. obli(|. ext. siiperlic, the deeper one with the M. obliip 

 ext. prof, ot Urodeles. Consecpieiitly the M. obliq. ext. of I'rimales 

 is homologous with the M. obli(|. exI. siq)erlic., whilst the Alemlirana 

 abdominis intermedia is the lioinologoii of (he Miisciilus obli(|. ext. 

 profundus of I'rodeles. 



The direction of the fibres of the AI. oblii|. ext. prof, of I'rodeles 

 differs little from that of the M. obli(|. ext. siiperlic. The abdominal 

 muscle, which with ancestral forms of Primates was found in the 

 jtlace of the Membrana intermedia, will also in all probability, with, 

 regard to the direction of its fibres, have corres|)onded with the 

 M. obli(|, exI. (siipeificialis ') of Primates. 

 i| \'. Im.slkr. bit.' iNiiiskflii (les .'^liuiunes. .Iciia i'.Uli. 



