76 T. H. MORGAN. 



Plate VIII. — Macerations of Eye of Phoxichilidium. De- 

 velopment of Eye of Tanystylum and Section of Ganglia 

 of same, etc. 



Fig. 40. Retinal elements of eye of Phoxichilidium obtained by 



maceration in Haller's fluid. 



Fig. 41. Others of same. 



Fig. 42. Collection of three retinal elements, from maceration. 



Fig. 43. End of cell showing bacilli, from a maceration in sul- 

 phuric acid and sea-water. 



Fig. 44. Retinal cells of outer surface of middle layer of Pallene. 



Fig. 45. Pigment cells of inner layer of Phoxichilidium. 



Fig. 46. Eye of Tanystylum-larva. Longitudinal section of 

 anterior and only pair. Stage 4. Zeiss 4 F f . 



Fig. 47. Same of older larva. From posterior pair. Stage 5. 



Fig. 48. Same of one posterior eye of older larva. Stage 6. 



Fig. 49. Same of one posterior eye of older larva. Stage 7. 



Fig. 50. Section in same series as last. 



Fig. 51. Same of older larva. Stage 8. Zeiss 4 F f . 



Fig. 52. Cross-section through posterior part of body of larval 

 Tanystylum, showing beginning of a pair of ganglia, etc. Zeiss 4 D % . 



Fig. 53. Pair of ganglia with ventral organs disappearing. 



Fig. 54. Pair of ganglia with cavities of ventral organs. Zeiss 4 

 Df. 



