10 ART. 15. — H. OIISIIIMA : SOME OBSERVATIONS 



The coloured part always coincides with the extent of the 

 lens ; for instance, when such of the organs as open obliquely to 

 the surface, as, f.i., the branchiostegals, is seen from the surface, 

 the coloured part is scarcely visible, being covered by the lateral 

 portion of the reflector, while the whole of the parabolic area, where 

 the gelatinous tissue and the median wall of the reflector come 

 directly in sight, is white and argeuteous. If the amethyst col- 

 our is due to the reflector, why should not the former come 

 into evidence where the latter is shown to such an advantage ? 

 Moreover, the colour fades within some hours after preservation. 

 It is, consequently, highly probable that the amethyst colour is 

 inherent in the lens. 



In the thoracic organs, arranged in double rows on the 

 ventral side between the pectoral and pelvie fins and opening 

 vertically to the surface, the diameter of the largest one as 

 measured at the orifice was 0.95 mm., while the posterior anals, 

 which form hindmost rows in the caudal region, measured from 

 0.6 to 0.45mm. across, the length of the fish being 42mm. 

 exclusive of tail. 



Histology, 



The luminous organ of llaurolicus is composed of the fol- 

 lowing elements: 1) layer of pigment cells, 2) reflector, 3) 

 connective tissue, 4) photogenic body, 5) lens, 6) gelatinous 

 connective tissue. The reflector may be absent, as, f.i., in the 

 anteorbital organ. 



The reflector is highly differentiated and consists of two 



parts of different structure, the inner and the outer.''' The 



* These are not identical with Maxgoxd's ''innere" and "äussere" reflector, which 

 are merely parts of my inner reflector. 



