Luminous Organs uf Selachian Irishes. 



501 



between tlie epidermi.s and tlie cutis could not be establi.slied 

 with jiic'cisioii on material whicli had been preserved in a 

 solution of formalin. Certain it is that here, too, an incur- 

 sion ot'large pigment-cells into this prominence took place by 

 means of the straud leading to it, and which itselt" is enveloped 



Fi«. 1. 



Microscopical sectioa of the luminous orgHH of L. rostrat-is. 



by them. This strand seems to consist of a fibrous tissue 

 admitting a nerve of considerable size. On comparing it with 

 the luminous organ descril>ed by Johann, it appears to me in 

 proccgs of atropliy, and may possibly be met with only in a 

 state of perfect develo{)ment in the fully gestated embryo, 

 afterwards becoming rcsorbed. 



Fig. 2 shows the luminous organ in correlation with the 

 surrounding scales. From a bulbous centre, which latter 

 represents the swelling seen in fig. 1, extend on two side* 

 some epitlndial stran<ls which are covered by pigment. 



These scales differ from the normal ones in the following 

 points : — 



(1) \\y having a more abundant pigmentation of their 

 pulpa, thus making the parts which these organs occupy, and 

 which are already prominent under ordinary macroscopicai 

 observation, more conspieuous. 



