VOL. XIII, PP. 47-51 MAY 29, 1899 



PROCEEDINGS 



OF THK 



BIOLOGICAL SOCIETY OF WASHINGTON 



THE EYE OF BYBLIS SERRATA. 

 BY SYLVESTER D. JUDD, Pir. D. 



Byblis serrata is an Amphipod Crustacean, which belongs to 

 the family Gammaridx, l>ut has totally different eyes from Gam- 

 marus. A pair of these eyes projects from either side of the 

 cephalon and any one of them calls to mind the vertebrate 

 eye, because it has a biconvex lens and a fluid-filled space with 

 a retina below. A section through the chief axes of the eye 

 of Byblis would first show a large lens, which has been secreted 

 in concentric shells by a thickened layer of lentigen. Fig. 4, I. 

 continuous on either side with the thinner hypodermis A, which 

 is gorged with scarlet pigment that envelops the eye like a cornu 

 copia, thus shutting out all the rays that might reach the retina 

 without first passing through the lens. Under the lentigen is a 

 humor space, s. Below and proximal to this space is a layer of 

 columnar cells, a, which is continuous on either side with the 

 hypodermis. This layer of cells has secreted a strong cuticula 

 on its outer boundary, which borders on the space, and just prox 

 imal to this layer are the omatidia (which, of course, lack the 

 corneal cuticula). The most distal element of an omatidium is 

 a granular columnar body (cell product), '/. Below and proximal 

 to this body, the remainder of the omatidium with its refractive 

 cone and retinula is practically identical with the omatidium of 

 Gammarus, minus of course, the corneal cuticula, for in the re 

 tinula of both crustaceans there are five retinal cells with pig 

 ment and four rhabdomeres. 



METHODS. 



The material employed in studying the eye of Byblis serrata 

 was obtained at Mr. Alexander Agassiz's laboratory, at Newport, 



13 BIOL. Soc. WASH., VOL. XIII, 189'J (47) 



