190 CEYLON PEARL OYSTER REPORT. 



Spicules. Apparently all stylote and all long (Plate XIIL, fig. 4), but varying 

 much in thickness ; usually only very slightly curved (towards the base), but some- 

 times crooked ; broadly rounded off at the base, which may be somewhat narrower 

 than the middle part of the spicule, and gradually and sharply pointed at the apex. 

 The stouter forms measure about 1"18 millim. by - 0328 millim. In the digitiform 

 processes they are a good deal more slender, and slender forms also occur intermingled 

 with the stout ones in the body of the sponge. 



R.N. 202a (deep water off Galle and onwards up West Coast of Ceylon). 



Axinella halichondrioides, n. sp. Plate XII., fig. 7. 



Sponge encrusting, extended horizontally. Upper surface somewhat convex and 

 rather uneven, with small monticular elevations, each bearing a single vent, scattered 

 at fairly regular intervals ; granular (minutely conulose) between the elevations, the 

 conuli being normally covered over by a thin, transparent dermal membrane. Colour 

 (in spirit) light brown ; texture firm and compact, columnar in vertical section. 

 Greatest breadth of specimen about 64 millims. ; thickness in the middle about 

 16 millims. Height of vent-bearing projections up to about 2 millims. Diameter of 

 vents about 1 millim. Distance between vents about 9 millims. 



The skeleton consists chiefly of very stout but rather loose and irregular and only 

 slightly plumose columns of spicules running vertically to the surface and ending in 

 loose brushes in the small surface conuli. These columns contain a very large number 

 of spicules and are connected together by short, loose bands of spicules running across 

 the interspaces at right angles. There are also a large number of spicules irregularly 

 and loosely scattered through the soft tissues. 



Spicules. Mostly oxeote (Plate XII., fig. 7, a) ; gently and uniformly curved, 

 gradually and sharply pointed at each end; size about 0'31 millim. by O'Ol millim. 

 A few styli of about the same size also occur (Plate XII., fig. 7, b, c). 



This species resembles pretty closely Thiele's Axinella incmstans (39) from Japan, 

 but its spiculation shows it to be distinct. 



R.N. 75 (outside pearl banks, Gulf of Manaar). 



Phakellia, Bowerbank. 



Axinellidffi of compressed, fiabellate (or cup-like) form, usually with vents on one of 

 the flat surfaces and inhalant pores on the other. Without microscleres. 



Phakellia donnani (Bowerbank). 



1873, Isodictya donnani, Bowerbank (8); 1887, Axinella donnani, Dendy (2). 



There are a dozen specimens of this characteristic species in the collection, in various 



stages of growth. The spiculation, as usual in the Axinellidse, is somewhat variable, 



and oxeote as well as stylote spicules occur. In view of the cup-shaped (or sometimes 



fiabellate) form (see fig. 4) it seems desirable to remove the species from the genus 



