EVES AND NEURAL GLANDS IN CYCLOSALPA. 2Q/ 



Cyclosalpa dolichosoma-virgula the positions of these parts is the 

 usual one ; in Salpa punctata the shifting has been slight, about 

 45 , in Thalia the rotation is greatest, 180 or more. The 

 position and arrangement of the nerves in TJmlia confirms this 

 interpretation. 



Remembering the rotation that has occurred in Salpa punctata t 

 it seems clear, on comparing Fig. 5, PI. VIII., and Fig. 12, PI. 

 IX., that the group of rod-cells lying behind the origin of the optic 

 nerve, in the dorsal part of the ganglion, in 6". punctata corre- 

 sponds to the postero-dorsal protuberance from the ganglion in 

 Cyclosalpa dolicliosoma-virgula, although in the latter species rod- 

 cells are not found in this region. There is great diversity 

 between species in the extent to which groups of rod-cells are 

 developed in the periphery of the ganglion. A similar postero- 

 dorsal protuberance containing no rod-cells is found in Cyclosalpa 

 pinnata(Y\g. 18, PI. IX.). 



LITERATURE CITED. 

 Goppert, E. 



Untersuchungen liber das Sehorgan der Salpen. Morph. Jahrbuch, Bd. 19, Heft 3. 

 Metcalf, M. M. 



The Eyes and Sub-Neural Gland in Salpa. Mem. Biol. Lab. Johns Hopkins 

 Univ., Vol. II., Part IV. 



