ASTROSCLERA WILLEYANA, 



THE TYPE OF A NEW FAMILY OF SPONGES. 



By J. J. LISTER, M.A., F.Z.S., 



Fellow of St John's College and Demonstrator in Comparative Anatomy in the 



University of Cambridge. 



With Plates XLV— XLVIII, and three Figures in the text. 



CONTENTS. 

 Introductory Remarks. 



E.XTERNAL CHARAeTERS, p. 460 : 



of the Lifu .specimens ; of the Funafuti specimen. 

 Methods, p. 462. 

 The Skeleton, p. 463 : 



microscopic characters ; mineralogical characters ; organic basis ; origin of the skeletal elements ; 

 the arrangement of the skeletal canals. 



Mode or Growth, p. 466. 



The Specific Relationship of the Specimens from the two localities, p. 468. 



The Soft Tissues, p. 468 : 



the gelatinous layer at the surface and the pores; the ciliated chamlicrs: the canal sj'stem. 

 Reproduction, p. 470. 

 State of Preservation, p. 470. 

 Affinities, p. 471. 



Discussion of resemUances to Madreporaria, p. 471 ; the isolated position of Astrosclera among 

 sponges, p. 472 ; comparison with the Pharetrones, p. 473 ; on the Spherulitic structure seen 

 in the Pharetrones from St Oassian and elsewhere, p. 476. 



Definition of the Family Astroscleridae (new family, genus and species), p. 479. 



Conclusion, p. 480. 



In the collections brought home by Dr Wille}- from the \\'(>slern Pacific were 

 four specinien.s of a peculiar hard white oigauism which lie found growing on dead 

 coral, at a depth of 3.5 fathom.s, in Sandal Bay, Lifu, Loyalty Islands. These he 

 placed in my hand.s for examination. A .short account of the results I had arrived 

 at was given at the meeting of the British Association at Dover in September, 1899. 

 As the organism appeared to be new, the name Astrosclera willeyuna wa.s proposed 



