PHOTOPHORES OF DECAPOD CRUSTACEA 



353 



Immediately behind the reflector formed by the proximal granular masses of the 

 photogenic units is situated a conical mass of nuclei (Fig. 24, n.) which differ 

 from all other adjacent nuclei. They are closely crowded and are deeply staining, 

 showing a prominent nucleolus, and being larger than the nuclei of the chitogenous 

 epithelium, which in my preparations show no obvious nucleolus, they are readily 



phot add. 

 n.conn.t 



phot nv. 

 n.ngl 



n.chit.ep. 



n.r.c. 



Fig. 24. Part of a transverse section through the abdomen of Systellaspis affiiiis to show the stnicture of the uropod 

 photophore. Mallory's triple stain. /./. inner layer of lens; l.o. outer layer of lens; l.s. lens-shaped septum extending 

 across photogenic unit; «. one of a large number of densely packed nuclei lying within the fibrous reflector; n.chit.ep. 

 nucleus of chitogenous epithelium; n.conn.t. connective tissue nucleus; n.ngl. neuroglia nucleus; n.r.c. nucleus of cell 

 producing reflector layer; phot.nv. nerve to photophore; phot.u.cl.a. clear area of photogenic unit; phot.u.d. distal mass 

 of photogenic unit; plwt.u.n.f. nerve fibrils to photogenic unit; phot.u.p. proximal mass of photogenic unit; r. reflector. 



