(39) 



verse section we liiid tliereCoin^ these dorsal coi-iiiia as lamellae in 

 juxtaposition (fig. VI I (-D). 



When the direction of the myotome is reversed al a line of fol- 

 ding, the same happens with the sense of the inclination, so that 

 these i)ai'ls show a slight ci'anial inclination. Tiie folding of the 

 myotome together with the inclination pro(lnc(\s the elongated and 

 })eakshaped foi-m of the myotome at tlu^se lines of folding. The 

 myotomes thns co\'ei' each other as hollow, pointed tuhes telescoped 

 into each other. In the transverse section (lig. Vil) I indicates the 

 section of the first |)eak directed candally, 2 the |)eaU tnriied towards 

 the head and 8 the second peak tiirned to the caudal (Mid of the 

 body (fig. VT resji. 1, 2, 3). In conse(pience of the inclination of the 

 dorsal part of the myotome, these lines of folding are not quite at 

 right angles to the sagittal axis, hnt are also slightly inclined. This 

 is the reason why we tiiid only jiart of these lines in a transA^erse 

 section, wdiich is normal to the sagittal axis. 



From a transverse section Ave can iudoe the extent of the mnscniar 

 overla})se. Concordant with 'the inci-easing inclination from the mid- 

 dorsal line t(^ the first lateral line, we see ihe overla|)se increase to 

 about •'/,. At the knee the inclination ra|)idly decreases. Tn the 

 lateral j)art of the myotome the inclination is insignilicant and the 

 overlapse less than \l.,. In the \'entral part the inclination increases 

 at first and then decreases to^^'al'ds the mid-\'entralliue ; th(Miiuscular 

 overlapse does not surjiass \.,. The ventral part tei'iiiinates at the 

 mid-ventral line in a ventral coruu 'CV fig. VII, tig. V) turned 

 cranially. This ventral cornu is much shorter than the doisal cornii. 



In order to get some idea of tlie dimensions of the myotome 1 

 have measured the length of each of the three parts into which the 

 myotome is divided up. These measurements have been made over 

 the surface of the myotome and this surface was also followed Avherc 

 it is folded in. In this way 1 liaAc found for the myotome described: 



Length of the dorsal part 350 mm.: Ihe lateral part 1)0 mm. -,1116 

 ventral jiart 190 mm. The length of the wIk^Ic myotome is therefore 

 (530 mm. and of this ■''/,„„ belong to the dorsal region. 



T have made the same measurements in the myotome of Fetro- 

 'myzon. If it be conceded that tli(> points A' (lig. 11 and tig. VI) 

 where the knee is located in both myotomes, ar(M'ori-es|»ou(ling jwints, 

 I have found : Length of the doi'sal part, from Ihe mid-dorsal line 

 to the knee 33 mm. : tlu^ latero-\entral i)arl. from the knee lo the 

 mid-ventral line, 20 mm. The whole length of llie myotome was 

 therefore 59 mm., and of this also ''/i„„ is contributed to the 

 dorsal region. 



