444 JANE STEPHENS: ATLANTIC SPONGES 



Several pieces of this species were obtained, encrusting the stems of a hydroid to 

 a height of about 45 mm. One small specimen is growing at the base of a specimen 

 of Siphonochalina anonyma n. sp., and another is at the base of the young specimen 

 of Homoeodictya compressa (Esper). 



The colour in spirit is dark purple grey. 



The spicules agree exactly in character with those of the type-specimen, but the 

 megascleres are slightly shorter than those of the type. 



The measurements of the spicules are as follows : — (l) Acanthostyli belonging to 

 two groups, 0'15-0'18 mm. in length by O'Oll mm., and 0'09-0'115 mm. in length 

 by 0'004 mm. (3) Anisochelse, 0*019 mm. long. (4) Bipocilli, 0'015 mm. in length. 



Clathria lobata Vosmaer. 



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

 specimen. 



The only specimen obtained consists of a broad, fan-like lobe, 36 mm. in height 

 by 40 mm. in width and 9 mm. in thickness, rising directly from an approximately 

 circular base, 15 mm. in diameter. A short, thick, finger-like lobe is given off on 

 either side of the fan-like expansion. The surface is apparently even, but, under the 

 lens, it is seen to be minutely hispid. The dermal membrane is thin and is firmly 

 attached to the underlying tissues. The pores are numerous, and the oscula are not 

 apparent. The consistence is firm, but slightly compressible. 



The colour in spirit is pale greyish yellow. 



The main skeleton consists of a reticulation of well-marked horny fibres, cored by 

 large, smooth styli and echinated by short acanthostyli. The principal fibres are 

 usually 0'07 to 0'13 mm. thick. They run upwards through the sponge, branch and 

 curve outwards to the surface, where they pierce the dermis, and end in tufts of 

 spicules. They contain several rows of large, smooth styli arranged in a slightly 

 plumose manner, so that sometimes the tips of the spicules project from the sheath 

 of spongin enveloping them, and add to the echination of the fibres. The main 

 fibres are usually the length of the large, smooth styli apart. The transverse fibres 

 are at right angles to the principal ones. They are about 0'025-0*05 mm. thick, 

 and consist of one or several styli surrounded by a distinct sheath of spongin. 

 Occasionally they are echinated by one or two acanthostyli. Large numbers of 

 megascleres are scattered through the sponge, and in places the arrangement of the 

 skeleton is irregular. 



The dermal skeleton consists of vertical brushes of closely set slender styli, which 

 project slightly beyond the surface of the sponge. The terminal styli of the main 

 fibres also project and add to the hispidation of the surface. 



Spicules. — (l) Large styli of the fibres. — These are smooth, fusiform, with 

 slightly curved shaft, usually between 0'25-0'35 mm. in length, with a maximum 



