No. 2.] EVES OF POLYCHyETOUS ANNELIDS. 189 



Odontosyllis hicifera Verrill. 



These annelids are found very abundantly, swimming at the 

 surface with Autolytus. While Autolytus is positively helio- 

 tropic, these syllids are markedly negatively heliotropic, and 

 at the same time able to secrete an unusual amount of mucous 

 and to give out a brilliant green phosphorescent light. 



The eyes are four, and dorsal in position ; the anterior pair 

 much the larger. The pigment is golden-red when fresh ; in 

 Perenyi's hquid it dissolves, in part, as a golden liquid. From 

 surface views there is no evidence of a lens ; but in sections, a 

 peculiarly constructed lens connected with the cuticle is demon- 

 strable. The long retinal rods (Fig. 46) appear directly con- 

 tinued as rod-like elements of the clear refracting mass, or lens, 

 filling the optic cup. Within this mass, however, there are 

 rounded highly refracting bodies or miniature lenses of various 

 sizes, not divisible into rod-like elements. One of these is quite 

 large, as seen in the figure. A few others are present, scattered 

 about, and often so small as to be contained within one of the 

 rod-like elements of the lens, as on the right. The entire lens, 

 or refracting mass central to the retinal-rod layer, is thus com- 

 posed of continuations of these rods, except where the large 

 especially refractory globules are found. The smaller globules 

 are within the continuations of the retinal rods. 



A slender cylindrical stalk connects the lens with the cuticle 

 (Fig. 46), and this presents longitudinal situations suggesting 

 that the attenuated lens elements are here continued up to the 

 cuticle ! 



The retina is like that of Autolytus, but is not separable from 

 the brain. Its isolated cells are densely pigmented, even along 

 the nerve processes, as represented in Fig. 48. 



Pedophylax longiceps Verrill. 



In an adult female with sexual setae the four eyes have yellow- 

 red pigment and dense lenses sending up conical slender stalks 

 to the cuticle, much as seen in the last annelid (Fig. 46). The 

 lens, however, has the appearance of that in Autolytus (Fig. 44), 

 though not projecting from the retinal cup. 



A summary of the results obtained in this family seems 

 scarcely necessary, as the eyes here repeat much that is found 



