On a Keiu Species of Leucosolenia. 17.9 



Ute, whence the specific name lUeoides. The wall of the 

 tube is about O'lo mm. thick, the mesoderm being, as in 

 L. stolonifer, very strongly developed for a Homocoel 

 sponge. 



The skeleton consists of quadriradiate and two kinds of 

 oxeote spicules. The quadrii-adiates are arranged as usual 

 in the thickness of the mesodei'm towards the inside of the 

 sponge- wall, the facial rays lying parallel to the gastral 

 surface, the basal ray directed away from the osculum, and 

 the apical ray projecting into the gastral cavity. These 

 spicules are markedly sagittal, the oral rays being widely 

 extended and distinctl}^ recurved towards the basal. All 

 three facial rays are long and slender, but the basal is much 

 more so than the orals and is slightly hastate ; all three are 

 fairly sharply pointed. In an average-sized spicule the oral 

 rays measure about O'lSG b}' 0-0082 mm. (near the base) 

 and the basal about 0"31 by O'OOG mm. (near the base), but 

 of course there is a good deal (^f variation, and I have 

 measured the basal ray up to ()42 mm. in length. The 

 apical rays are very strongly developed ; long, slender and 

 sharply pointed ; usually more or less crooked and varying 

 greatly in length ; the average length is perhaps about 

 Oio nmi., but this is often greatly exceeded. 



The oxeote spicules may be divided into two classes accord- 

 ing to their shape, size and position in the sponge. (1) Very 

 large spindle-shaped oxea, completely imbedded in the outer 

 portion of the sponge wall and arranged parallel to the long 

 axis of the sponge. These spicules are usually straight 

 and symmetrically fusiform, very thick in the centre and 

 tapering gradually to a fine point at each end. Fully grown 

 examples measure a little over 1 mm. in length and about 

 ()'()65 mm. in greatest thickness (in the centre). They are 

 placed pretty close together side by side in a single layer. 

 (2) Much smaller oxea projecting from between the large 

 ones and abundantly echinating the outer surface of the 

 sponge. These spicules are rather slender, often slightly 

 curved or even crooked, fairly gradually sharp-pointed at 

 each end, but with the outer end often bent slightly though 

 sharply to one side, like a bayonet ; size about 022 mm. by 

 0-008 mm. The colour of the sponge in spirit is yellowish- 

 white. 



As already pointed out this species is nearly related to 

 my Leucosolenia .stolonifer, but it appears to be even more 



N 2 



