286 



EllYLUS SOLLASII. 

 LOCALITIES AND NATURE OF ENVIRONMENT (continued). 



There can he no doubt that the seven sponges described above arc very 

 closely allied, still they differ to a certain extent in size, shape, colour, and 

 spiculation. As to the size it is to be noted that the forms A and B of race 

 I are very much smaller than the othere. Since, however, the si)iculation of 

 these small specimens exhibits immature charactci-s, there can be no doubt 

 that they are young forms, that their small size is merely due to their age 

 and of no systematic importance whatever. Neither can any importance be 

 attached to the differences in shape, since they lie well within the limits of 

 individual variation usual in sponges of this kind. The differences in colour, 

 which ranges from dirty white to dark chestnut-brown, are indeed great. If, 

 beginning with the lightest coloured one, we arrange the fornxs in the order of 

 the degree of their pigmentation, we get, 1) race I, form C, 2) race I, form D, 

 3) race II, 4) race III, 5) race I, form A, and G) race I, form B. If, beginning 

 with the deepest, we arrange them in the order of the depth of the water at the 

 place where they were found, we get, 1) race I, form D, 152-207 m. ; 2) race I, 

 form C, race II and III, 7S-133 m. ; and 3) race I, forms A and B, 42-44 m. 

 Although it is unknown which of the specimens of race I, form C, race II, and 

 race III grew in deeper, and which in shallower water, we see that the depth 

 of the locality is, on the whole, roughl}' in inverse proportion to the degree of 

 pigmentation. The darkest forms, the partly or wholly dark chestnut-brown, 

 race I, forms A and B, grew in the shallowest water, at a depth of 42-44 m., to 

 which, in clear tropical sea water, considerable day light penetrates. This 

 and the fact that in some of the specimens the upjier protruding parts are 

 darker than the basal, lead me to suppose that these differences of colour are 



