1868.] DR. J. E. GRAY ON XYLOSPONGIA COOKII, 637 



4. Note on Xylospongia cookii, a New Genus of Palmated 

 Sponges in the collection of the British Museum. By 

 Dr. J. E. Gray, F.R.S., V.P.Z.S., &o. 



In the British Museum is a very extraordinary, lobed, woody, pal- 

 mated body, with eight flattened, irregularly netted, strap-like lobes. 

 It has been in the collection for many years, but has not been 

 named ; indeed grave doubts have been entertained if it were not the 

 woody skeleton of some vegetable production. 



Being without any habitat, it has been left unnoticed, in hopes 

 that a second specimen might occur accompanied by some details of 

 its history. 



It was doubtless collected on the sea-coast, as one of its sides is 

 more or less covered with the undervalves of some very young 

 oysters and other attached marine shells. 



Being desirous of knowing more of its structure, I submitted a 

 small fragment of it to the examination of Mr. M. C. Cooke of the 

 India Museum, who informs me there can be no doubt of its being 

 a sponge belonging to my family Halichondriadce, the substance of 

 it being studded with abundance of smooth, slender, fusiform, shghtly 

 curved sihceous spicules. I have named the species after Mr. Cooke. 



Xylospongia (Fam. Halichondriadce). 



Frond compressed, fan-shaped, divided above into strap-shaped 

 flat lobes, rather wider at the ends. Root an expanded disk. Stem 

 thick, woody, subcyhndrical below, compressed above and expanded 

 into a flat fan-like frond, which is divided above into eight or ten 

 strap-hke flat lobes, hke the fingers on the hand, the lobes varying 

 rather in width, the outer one on each side being the narrowest. 

 The root and stem are sohd, wood-hke ; the upper part of the broad, 

 expanded, fan-like part of the stem more or less pierced with differ- 

 ent-sized perforations, and the part divided into strap-like reticulate 

 lobes, which are generally rather wider at the ends. The expanded 

 part of the stem and the strap-like lobes are all formed of parallel , 

 cylindrical filaments, about as thick as twine, wliich in the upper part 

 of the stem are united together by woody matter, leaving only a few 

 perforations between them ; but in the strap-like lobes the filaments 

 are much more distinct, rather flexuous, inosculating where they 

 nieet their neighbouring subparallel filaments, united by the woody 

 material, which is not quite so thick as the filaments. The surface 

 is rather rugose, the minute rugosities of the stem and filaments 

 being placed longitudinally and parallel to each other. Spicules of 

 one kind, minute, slender, fusiform, often very slightly curved or 

 arched. 



Xylospongia cookei. 

 Hah. . 



