172 



THREE CRUISES OF THE " BLAKE. 



by him from a depth of 1,075 fathoms off the Bermudas. It 

 must have attained at least a foot in height. 



Another most common and at the same time most exquisite 

 type of Hexactinellidse is Aphrocallistes Bocagvi (Fig. 522), 



Fig. 522. Aphrocallistes Bocagei. f . 



which has been dredged by the " Blake " in depths of from 164 

 to 400 fathoms. It is also found in the eastern basin of the 

 North Atlantic. The network appears to be formed by the co- 

 alescence of stellate spicules. These sponges are often attached 

 to corals and soldered together, so as to form large convo- 

 luted masses. Dactylocalyx is one of the most characteristic 

 of the Caribbean types. The shape of Dactylocalyx pumi- 

 ceus (Fig. 523) varies from that of a cup to that of a flat 

 dish attached by a short stem. The surface is furrowed and 



Fig. 523. Dactylocalyx pumicens. 



