314 



A. TEU AO : 



certain affinity to the photogenous cells and, at the same time, a marked 

 difference from the connective tissue. Thus, Freeborn's picro-nigrosin 

 stains it yellow, as it does the photogenous cells ; while the same reagent 

 stains the connective tissue blue. 



In some photophores of the species the reflector may be entirely 

 wanting. I have found it often absent in those situated in the median line 

 of the sterilite of cephalothoracic segments. In these cases there exists in 

 place of the missing reflector, i. e., between the basement membrane and 

 the pigment mantle, a narrow space occupied by the ordinary loose 

 connective tissue which is continuous with that of a more internal situation. 



6) The pif/menf mantle. — A cup-like pigmenr mantle of a reddish 

 color exists, holding in its hollow the marginal cells of the photogenous layer 



and the entire proximal convex 

 surface of the reflector (pi, figs. I 

 and 3). Proximally the mantle 

 sends out a number of long 

 chromorhyzae. Examined in the 

 material preserved in glycerin, it 

 is seen to consist of a dense ac- 

 cumulation of three kinds of pig- 

 ment granules, viz., the red, orange 

 and black, as is also the case with 

 the pigment flecks under the hypo- 

 dermis of the general body surface. 

 In weak ìormalin the pigment remains for some time but is ultimately 

 dissolved away. In most other fixatives, f. i., in alcohol," it quickly dis- 



* A short time after the animal is thrown into alcohol, there come distinctly into view a pair 

 of reddish-colored transverse bands behind the base of the fifth peraeopods, standing out 

 pronouncedly on the now depigmented body surface. They seem to agree completely with 

 the bands which Cornière (Note préliminaire sur les Eitcypìiotes recueillis par S. A. S. le 

 Prince de Monaco à l'aide du filet ;1 grand ouverture. Bull. Mus. Océan. Monaco, No. 48, 

 1905, p. 4, fig. 7) has described from Hoplopliorus grimaldi, calling them " un organe 

 lumineux en forme de longue bande." Their structure has remained unknown to me. Any- 

 way, they are certainly not luminous organs in S. preliaisilis. 



Fig- 3- 



Optical section through second photophore 

 of sixth abdomianl sternite. Glycerin 

 material. X 200. /, lens; pi, pigment- 

 mantle. 



