312 University of California Publications in Zoology [Vol. 11 



form a little cushion or bnlb. Where this ridge-like thickening 

 comes in contact with the rim (>•., pi. 13, fig. 1) of the bell a 

 saucer-like depression (pi. 14, fig. 5) is formed. On the cushion 

 and extending into the depression is located the eye-spot, which 

 can be detected by the naked eye only as a little patch of reddish- 

 purple pigment {oc, pi. 13, fig. 1). 



The pigment is not always in a round mass as one might be 

 led to suspect. It con.sists of two colors, red and brown, and 

 assumes in the living form numerous and varied shapes and 

 manners of distribution of the colors, even in the same animal 

 on different tentacles (pi. 15, fig. 8). Some of the masses are 

 seen to be concentrated into a very deep, dark, red-and-brown — 

 almost black — dot, with no outlying granules. In others the red 

 is scattered evenly throughout the saucer-like depression with 

 apparently no concentration at any point. Another appears with 

 scarcely any pigment, so that only a suggestion of pink over 

 the surface is seen. Several seem to contain a large amount of 

 red pigment either concentrated about a large, dark-brown center 

 with only a few scattering red grains, or running out from the 

 brown center in various w^ays (pi. 15, fig. 8). There may be a 

 single, long narrow streak running distally from the center for 

 a distance of two or three times the diameter of the cushion. 

 Again there may be two red lines running distally for an equal 

 or for unequal distances, while one line may contain a consider- 

 ably larger amount of pigment than the other. Or it may assume 

 the form of a wide lobe extending down over the cushion from the 

 brown mass. A general downward tendency is noticeable in these 

 pigment streamers. 



A single tentacle examined in section with tlie low-power (pi. 

 14, fig. 5) reveals the eye to be a cup-shaped or bud-like swelling 

 formed by the thickening of the ectoderm of the tentacle at that 

 point. The lower edge or rim of the cup is a little larger or 

 higher than the upper. Viewed from the side, the center of the 

 cup-like depression is seen to be nearly filled by a little, clear, 

 cone-shaped projection. This extends almost to the edge of the 

 rim and in some cases protrudes beyond it. This is the lens or 

 "glass body" (Is., pi. 14, fig. 4). The bottom of the cup is filled 

 with dark-brown and red pigment extending out in all directions 



