ASTROSCLERA WILLEYAXA, THE TYPE OF A NEW FAMILY OF SPONGES. 



461 



only from parts of its upper surface. At these parts rounded bosses of different sizes 

 have been formed (Fig. A, 1, and 2, b, b), and they, like the original disc, are perforated 

 by pores on their conve.x ujjper surfaces and covered on the sides by an imperforate 



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Fig. a. The Funafuti Specimen of Astbosclera. 



b, h. The bosses formed by later growth. ;/, ((. The disc-shaped expansion of the original growth. .<(. The 

 stalk of attachment. 



1. Side view. 



2. View from the base, with the stalk turned towards the spectator. Part of the specimen has been 

 cut away, and the base has been excavated by some boring organism. 



3. View of the surface of the large bosses formed by later growth. 



4. One of the radiate systems of large pores more highly magnified. 



5. View of the cut surface of the original growth, showing the radiate arrangement of the large canals 

 in the interior. 



cortical layer, which in some places appears to have spread from their base over the 

 adjoining regions of the surface of the original disc. 



The growth of the bosses repeats the character of that of the original disc, expand- 

 ing from the base ; and the greater mass of the new growth appears to have been 

 formed by the fusion of three originally distinct bosses. 



w. IV. 62 



