100 



cells of the optic ganglia. Small particles of coagulated haemolymph also 

 extend down the outside of the eye for about half of its length. 



Only a veiy few specimens of the young shrimp. P. antrorum, could 

 be obtained. These were from 5 to 5.5 mm. long. The optic stalk and eye 

 are much larger in pi-oportlon to the size of specimen (Fig. Ill) than in 

 the adult antrorum, but they are actually not as large as in the adult. 

 The internal structure showed no greater differentiation than in the ej'e 

 of adult. 



I am very grateful to G. H. Parl^er for assistance in the interpretation 

 of the structure of this ej'e. 



EXPLANATION OF FIGURES. 



Figure 1. Itorsal view of the front end of V. exilipes. 



Figure 2. Dorsal view of the front end of P. antrorum. showing the small 



eyes. 

 Figure o. Dorsal view of the front end of a young P. antrorum about 5 



mm. long. 

 Figure 4. Photograph of a cross section ihrdugh the optic stalk of P. 



anti'oruiii, showing rlic group of retinal hypodermal cells of 



the right eye. 

 Figure 5. Photograph of a longitudinal section through the optic stalk 



of P. antrorum, showing the group of retinal hypodermal 



cells. 

 Figure (i. Enlarged view (photograph) of group of retinal hypodermal cells 



sliown in Fig. 5. 

 Figure 7. Photograph of another group of retinal hypodermnl cells. Hor- 

 izontal section. 



BIBLIOGRAPHY. 



Benedict. James E.. '!>(;.— Preliminary (h'scription of a new genus and three 

 new species of crustaceans from an artesian well at San Marcos, Texas. 

 Proc. IT. S. Nat. Mus. Advance sheet. April 14, 1896. 

 Proceedings xviii. pp. G15-(il7. August 12. 1S9(!. 

 Chilton, Charles, '94.— The Subterranean Crustacea of New Zealand; with 

 some general remarks on the faiuia of caves and wells. 

 Trans. Liim. Soc. Loud., vi. pt. 2. 1894. 



