PLATE 10 



EXPLANATION OF FIGURES 



Cross-sections of adult. X 28 



25 Level of articulation of second cerabranchials with basibranchials, showing 

 the beginning of the pocket formed by the ceratohyoideus internus muscle. 



26 Level of the os thyreoideum and of the articulation of the epibranchial 

 with the first and second ceratobranchials, where the ceratohyoideus internus 

 begins to form the spiral. 



27 Level of the heart, showing the fourth levator and depressor of the gill 

 arches, and the spiral muscle toward the posterior region of the epibranchial. 



570 



