MYOLOGY OF FISHES. 



205 



the ventral and lateral tracts separate to give passage to the pec- 

 toral fins, as at a, h, fig. 134. 



From tills part forward, portions of the niyocommas undergo 

 that change, analogdus to anchjdosis, which justifies their being 

 regarded as distinc't longitudinal muscles : here the separated 

 ventral tract, fig. 135, a, derives a firmer origin from the clavicle, 

 and, ill consec[uence of the forward curve of the coracoid, it is 

 not i->n]y expanded hut lengthened out, in order to be inserted 

 there. But the serial homology of this fasciculus with the more 

 normal ventral portions of the succeeding myocommas, the h;ema- 

 pophysial attachments of which have not risen abo\'e the aponeu- 

 rotic state, is unmistakeable. The lateral portion of the anterior 

 myocomma, fig. 134, h,(j, is attached to the upper end of the coracoid 

 and to the scapula; the dorsal ])ortion,_/j to the suprascapula, par- 

 occipital and sujieroccipital. We recognise the dorsal portion of 

 tlie posterior cranial myocomma in the lasciculus called ' protractor 

 scapvdas,' fig. 134, c, the middle portion in that which is ox})osed 

 by the renroval of the operculum, and which extends from the 

 scapxda to the mastoid, fig. 137, 2G; the ventral portions in the 

 fasciculi continued from the coracoid forward to the hyoid, c, c. 



134 



Ic inusr)cs Qi licail, Pcrcli. xxxrir. 



fig. 135 : the corresponding portions of the more anterior cephalic 

 muscular segments may be recognised in d and 27, fig. 135. 



