224 MR. E. KIRKPATRICK OX THE PORIFERA [Mar. 6, 



" the specimen covered the submerged surface of a large stone to 

 the extent of over a square foot in area ; the crust was closely 

 adherent and very thin." 



The thickness of the crust is 2 mm. There are no oscules on 

 the fragments of the specimen. The surface is level and provided 

 with tufts of spicules -16 mm. in height, formed by the ends of 

 the main fibres. 



The skeleton is formed of main longitudinal fibres about 6 

 spicules thick ; at vaiying levels these fibres give ofi' transverse 

 secondaiy fibres 2-3 spicules thick, which meet the extremities of 

 those from other main fibres ; in parts where the main fibres are 

 closer together the secondary bundles reach across from one main 

 fibre to another, and the secondary bundles are thicker. 



There are traces of a basal spongin-lamella in the form of broken 

 scale -like fragments; but the spongin-fibres are reduced to mere 

 cushions, into which the ends of the basal oxeas are immersed. 



Spicules. — The megascleres are smooth curved oxeas 214xl8'5/i, 

 with subtornote ends ; frequently with a central knob. 



Micro-strongyles, scattered about in the tissues, are identical 

 with those of the gemmules, and in all probability have belonged 

 to those bodies. 



The gemmules are spherical, 380-425 yn in diameter, with one, 

 two or three pore-tubes, each I'ising about ISju beyond the sur- 

 face. The position of the pore-tubes varies, and when there ai'e 

 several they may be scattered over the circumference or close 

 together. In one instance a pore-tube is thick-walled, closed at 

 the end, and bent over. 



The gemmule-spicules ai-e micro-strongyles, arranged tangentially 

 in one or two layers on the chitinous capsule. When there is 

 only one layer, a tessellated or parquet-like pattern is discernible, 

 each tessella being made up of a parallel row of 4-6 micro- 

 sti-ongyles, and fitting in with neighbouring tessellse at varying 

 angles. When the layer is double it is difiicult to make ovit any 

 pattern ; here and there the spined ends of the spicules project 

 above the general level. 



The strongyles are of two kinds : in one, 70 x 12 /u, the spicule 

 is slightly curved, of nearly uniform diameter, spined all over 

 with short blunt vertical spines, but less so in the centre ; in the 

 other, which is 65 X 16 ju, the centre is nearly smooth, swollen, and 

 barrel-shaped, and tapering to the spined ends. 



Affinities. — The gemmule-spicules somewhat resemble those of 

 Spongilla simiatrana Weber, of which species Weltner describes 

 two African vaiieties ; in all these there are short spined micro- 

 strongyles, but there are no flesli-spicules in the new species, and 

 the megascleres are smooth, whereas in S. sumatrana and its 

 varieties there are flesh-spicules and the megascleres are spined. 

 Spongilla permixta Weltner from German East Africa, of which 

 species only the gemmules are known, has spined microstrongyles 

 for its gemmule-spicules, but these are much more slender, being 

 only 3 /i in diameter, and with recurved spines. 



In S. hiseriata Weltner the oxeas of the skeletal framework are 



