vou2, pt. 2.] A TAXONOMIC STUDY OF THE SALPIDAE METCALF. 91 



The eyes of the aggregated zooids of Salpa fusiformis (fig. 79) and 

 S. maxima are more nearly identical in structure than are the eyes 

 of the aggregated forms of any other two species of Salpa whose eyes 



Fig. 76. — Salpa fusifoemis, solitary form, paeasigittal section through the ganglion and one 

 limb of the horseshoe-shaped eye. x 197 diameters. from metcalf (1893, c). 



& j? s 



Fig. 77.— Salpa fusifoemis, aggregated zooid, dorsal view, x 2J diameters. (Drawn by Hoy t 



S. Hopkins.) 



Fig. 78.— Salpa fusifoemis, aggregated zooid, from the eight side. X 2J diametees. (Drawn 



by Hoyt S. Hopkins.) 



have been studied. The large antero-dorsal eye is shorter and more 

 compact in Salpa maxima, but this is the only observable difference. 

 In the ganglion there is a large mass of irregular degenerate rod-cells, 

 just posterior to the point of origin of the optic nerve. This is com- 



