554 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



Plate XLVI. 

 (Stage IX.) 



Figs. 146-151. Serial trausverse sectious, through the embryo oi A. saukyi, at the time vrhen 

 pigment is first deposited in the eye. In Fig. 146 the developmental history of the 

 retinal layer is well shown. x230. 



Fig. loU. Nearly median longitudinal section of embryo in similar stage. x58. 



Pig. 153. Sagittal section of similar embryo, showing degenerating elements in yolk below «lorsal 

 plate. X 58. 



REFERENCE LETTERS. 



J. I, first anteuna. 



A. II, second aatenna. 

 Ab., abdomen. 



B. C, blood corpuscle. 

 B. S., blood space. 

 cp., carai)ace. 



Deg., degenerating cells. 



Dp., dorsal plate. 



End., eudoderm. 



/(/., foregut. 



fa., fiber mass of nervous system. 



g. II-III, brain. 



g.c, ganglion cell. 



g. VI. a. , anterior gastric muscle. 



H., heart. 



hd., hypodermis. 



Hi/., hindgut. 



Lb., labrum. 



Md., mandible. 



Mes., mesoblast. 



ilit.f., flexor muscle. 



ocm., oesophageal commissure. 



e.g., optic ganglion. 



O. L., optic lobe. 



pi., punct substanz. 



pr., perineurium. 



lit., retinogen. 



S. 0. 6f., supra-o'sophageal ganglion. 



T., telsOD. 



Tc, transverse commissure. 



Th., thorax. 



Vac, vacuole. 



y., yolk. 



y. C, wandering cells. 



