440 JANE STEPHENS : ATLANTIC SPONGES 



of both dermal and main skeleton, and measure 0'37-0'58 mm. in length by 

 0'01-0'015 mm. The smaller occur in the brushes of spicules beneath the dermis, 

 and are also found in company with the larger styli throughout the sponge. They 

 measure 0'2-0'3 mm. in length by '005-0 "008 mm. 



The size of the spicules varies but little in the different specimens. 



Leucophlceus styliferus resembles in external appearance Leucophlceus massalis 

 of Carter, who also noted the likeness of his species to Halichondria panicea (4, 

 p. 323). It differs from L. massalis in possessing only styli, while the spicules of 

 Carter's species, as seen from a preparation of the type-specimen in the British 

 Museum, are largely oxea. The presence of oxea in Carter's type-specimen has 

 already been noted (F. F. Hernandez, in " Notas sobre Algunas Esponjas de 

 Santander," p. 17, Memoria presentada en la Universidad Central, Madrid, 1912). 



The genus Leucophlceus Carter (4) was not denned by its author. It is here 

 taken in the sense in which it is understood by Dendy, who gives a definition of the 

 genus in his important work on Ceylon sponges (5). 



Family Pcecilosclerid^;. 



Sub-family ectyonin^e. 



Hymedesmia oaculifera (Topsent). 



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



Specimens of a Hymedesmia, growing in thin patches on a small stone, agree 

 exactly in the arrangement of the skeleton and in the size and character of the 

 spicules with the descriptions given by Topsent (21 and 22) of this species. They 

 also agree closely with Lundbeck's description (13) of specimens taken by the 

 Ingolf Expedition. 



Several patches of the sponge, the largest about 24 mm. by 15 mm. in extent, 

 grow on a small stone, the thicker patches being pale yellowish in colour, the thinner, 

 bluish white. The spicules differ very slightly in length in these specimens, and the 

 dermal spicules differ as regards their shape exactly as described by Topsent for 

 the type-specimens from the north coast of Africa. In the thicker patches of the 

 sponge the spicules measure as follows : — {l) Acanthostyli, '09-0 "225 mm. long by 

 0'006-0'01 mm. (2) Dermal spicules rounded at one end and sharply pointed at 

 the other, or occasionally very slightly swollen at the ends (strongylo- to subtylo- 

 tornota), 0'15-0'18 mm. by 0'003 mm. (3) Isochelae arcuatse, 0'02 mm. in length. 



In the thinner patches the measurements of the spicules are : — (l) Acanthostyli, 

 0'07-0'19 mm. long by 0'005-0'009 mm. (2) Dermal spicules (strongylo- to 

 subtylota), 0'12-0'15 mm. by 0'0025 mm. (3) Isochehe arcuatse, 0'02 mm. 

 in length. 



The dermal spicules are sometimes very slightly polytylote, a condition mentioned 

 by Lundbeck as occurring in the corresponding spicules of the northern specimens. 



