THE DEVELOPMENT OF THE COMPOUND EYE OF 



CRANGON. 



J. S. KINGSLEY, SC.D. 



For several reasons I have thought it best to present my ob- 

 servations on the development of the compound eye in the 

 common shrimp, Crangon vulgaris, in advance of my complete 

 paper on the embryology of that form. This seems the more 

 desirable since I differ from Reichenbach, the most recent writer 

 on the development of the compound eye, in several important 

 points. 



Methods. 



The eggs were hardened by means of Pcrenyi's fluid, fol- 

 lowed by alcohol of increasing strength, a process which works 

 well with almost all arthropod tissues. In most instances they 

 were stained entire with Grenacher's alum-carmine, though in 

 some instances Kleinenberg's haematoxylin or Grenacher's 

 borax-carmine were employed. In the later stages, where the 

 deposition of pigment in the eye interfered with a clear vision 

 of all the structures concerned, the following course was fol- 

 lowed : The eggs were sectioned as usual, the sections being 

 fastened to the slide with Mayer's albumen fixative. After melt- 

 ing the paraffin and allowing the sections to drop into the ad- 

 hesive mixture, the imbedding material was dissolved in turpen- 

 tine, and this in turn was washed away with alcohol (95%). 

 The sections were then covered with a mixture of equal parts 

 of nitric acid and 95 % alcohol, which was allowed to remain 

 until the pigment was removed, — a process requiring from ten 

 to fifteen minutes. The slide was next washed with strong 

 alcohol, and the sections stained deeply with Kleinenberg's 

 haematoxylin, and the excess then removed with acid alcohol in 

 the usual manner. The sections were then mounted in balsam. 



