GILLS OF FISHES. 



481 



Lepadoy aster, and the Cyclopterus liparis have three biserial gills 

 and one uniserial gill ; the genera LopJiius, Batrachus, Diodon, 

 Tetrodon, Monopterus, Cotylis, have three biserial gills ; Malth&a 

 and Lepidosiren have two biserial gills and one uniserial gill ; the 



319 



320 



Section of branchial arch with a pair of processes, Section of branchial arch, a, with supporting frarae- 

 A', supporting the branchial plates, b, Cod. work of the plate-bearing processes, Cod. 



CCLXVIII. CCLXVIII. 



Cuchia {Amphipnous) has only two gills. The above enumeration 

 refers to the branchial organs of one side ; they are symmetrical 

 in all fishes, and the uniserial opercular gill is not counted, as not 

 being attached to a proper branchial arch. 



The branchial processes are bony, at least along the outer and 

 thicker border, in most Osseous Fishes (e.g. Salmo, Alosa, Gadus). 

 They are gristly, like the arches which support them, in the 

 Sturgeon, where they break up into delicate branched fringes, 

 along their outer margin. Small ( interbranchial ' muscles extend, 

 through the uniting septum, between the bases of the processes, 

 for effecting slight reciprocal movements. 1 



VOL. I. 



1 CXII. CXIII. 



II 



