COLLECTED BY THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 439 



the west coast of Ireland, which are 0"l75-0'425 in length and have a maximum 

 diameter of 0*009. 



The known distribution of Hymeniacidon caruncula is extended southwards in 

 the Atlantic by the discovery of the South African specimens, the species having 

 previously been obtained off the Azores and the Cape Verde Islands, as well as along 

 the western coasts of Europe from the British Isles to Portugal. 



Leucophlceus styliferus n. sp. (Plate XXXVIII, fig. 1 ; Plate XL, fig. 4.) 



Station 482. Houtjes Bay, Saldanha Bay, shore. 19th May 1904. Many 

 fragments. — Reit's Bay, Saldanha Bay, shore. 21st May 1904. One specimen. — 

 Station 483. Entrance to Saldanha Bay, 25 fathoms. 21st May 1904. Three 

 specimens. 



Nearly all the specimens are more or less broken. They grow in flattened cake- 

 like masses, about 10—15 mm. thick, or in irregularly rounded lumps. The largest 

 piece measures about 60 mm. in length by 45 mm. 



The texture is firm. The surface is apparently quite smooth, but under the lens 

 it is seen to be minutely hispid. 



The oscula average 1 mm. in diameter, and are usually raised a little above the 

 general surface of the sponge on ridges or on rounded prominences. 



The pores are grouped in the meshes of the dermal skeleton and usually measure 

 between 0'01-0'03 mm. in diameter. 



The specimens closely resemble Halichondria panicea (Pallas) in external 

 appearance (at least when spirit specimens of the two species are compared), and 

 also in the arrangement of the dermal skeleton and of the pores. 



The colour in spirit of most of the specimens is pale yellow or pale greyish 

 yellow, while two or three of them are pale greyish brown. 



The main skeleton consists of an irregular reticulation of rather closely packed 

 styli. More or less well-defined fibres, containing multiserially arranged styli, run 

 to the surface of the sponge and spread out in a slightly penicillate manner beneath 

 the dermis. The tips of some of the spicules pierce the dermis and project a little 

 beyond it, causing the minute hispidation of the sponge. 



The dermal skeleton consists of bundles of styli, similar to those of the main 

 skeleton, lying tangentially to the surface. These form a very regular reticulation, 

 in the meshes of which the pores of the dermal membrane are seen. The dermal 

 skeleton is, as already mentioned, exactly similar to that of Halichondria panicea, 

 except that here styli are present instead of oxea. In places the spicules are closely 

 packed together in sheets and the reticulation is obscured. 



Spicules. — The only spicules present are styli, which sometimes show a tendency 

 to become subtylostyli. They are fusiform and have a slightly curved shaft. The 

 styli fall into two groups according to their size. The larger make up the chief part 



TRANS. ROY. SOO EDIN., VOL. L, PART II (NO. 15). 62 



