3i8 /II.LIS. [Vol. XVIIL 



EXPLANATION OF PLATE VIL 



Fig. 36. External, or lateral view of the hyomandibulo-symplectic and 

 palato-quadrate apparatus. X 2. 



Fig. 37. Internal view of the same, with the opercular bones attached. 

 X 2. 



Fig. 38. Dorsal view of the ventral surface of the mouth and branchial 

 cavity. X 2. 



Fig. 39. Diagrammatic view of a section of the opercular demibranch. 



Figs. 40 and 43. Enlarged views of the bristles on the dermal pro- 

 cesses of the branchial arches. 



Figs. 41 and 42. Enlarged views of the dermal processes on the branchial 

 arches. 



Fig. 44. Enlarged view of the dermal rays of the gill filaments, showing 

 the associated muscles. 



