466 



CRUSTACEA MALACOSTRACA. 



"N 



9 a 



4 .-XiE 



ph 



FIG. 290. Section of the eye of Styloctieiron (after Chun), ax axial fibres ; c cornea ; con 

 crystalline cones ; F frontal eye : f.rud vestigial side-facets of frontal eye ; ga ganglion 

 cells ; ga* distal optic ganglion ; hyp hypodermal cells ; / lamellae of the luminous organ 

 in the eye stalk ; n' nuclei of the retinular cells which correspond to the vestigial corneal 

 facets of f.rvd ; nc Semper's nuclei ; nh nuclei of hypodermal cells ; nr retinal nuclei ; 

 M nuclei of iris pigment cells ; opt optic fibres ; pq.ir iris pigment ; ph luminous organ ; 

 ret retinula ; rfl, inner surface of reflector of the luminous organ ; S lateral eye ; str striated 

 body (it is uncertain whether this or the reflector is the seat of the luminous substance) ; v 

 blood-vessels. 



some Euphausiidae the endopodite of the last pair (in Euphausia 

 of the seventh and eighth) has disappeared, though the base 

 remains bearing the gills and the minute exopodite. On the 



