512 Mr. H. J. Carter o?i 



viz. Clathrina ventricosa, it will be more particularly described 

 there. At first I thought this was a fungoid spore with long 

 tubular tail-like appendage ; but its much larger size, absence 

 of septa, and the refractive granules of the interior issuing 

 through the tail seem to be opposed to such a view. 



7. Clathrma ventricosa. 



Individualized. Massive, lobate, sessile generally, or 

 attached by a plurality of attenuated portions of the body, 

 thus resting on such points, or not attached at all, but free 

 and floating, furnished with a large cloaca and contracted 

 mouth, or the same in a group with wide crateriform mouths. 

 Colour white or pinkish brown, the latter probably owing to 

 the proximity of a red-coloured sponge. Texture compara- 

 tively firm. Surface-structure consisting of a thick cortex of 

 radiates covered with deep, polygonal, infundibuliform de- 

 pressions or holes echinated round the inner ends and often 

 diaphragmed there by cribriform sarcode; built up of large 

 radiates, whose intercrossing rays give the polygonal form ; 

 almost in juxtaposition, and varying in size under l-20th in. 

 in diameter ; or with the same reduced, probably by friction, 

 to a white, homogeneous-looking, compact, cortical layer, in 

 which the same kind of holes are present, but without the 

 polygonal infundibular form, being simply subcircular and 

 more or less variable in size. Pores in the intervals between 

 the " infundilmlar depressions." Vents of two kinds, viz. 

 small and numerous and large and single ; the former, that is 

 the small kind, at the bottoms of the " infundibular depres- 

 sions " respectively, varying in size with that of the depres- 

 sions themselves, echinated &c. at the inner end, as just 

 stated ; the latter large and single, bordered by a thin lip of 

 fine structure about 1-1 6th inch wide ; both leading to a large 

 cloaca, whose surface is thickly beset with holes of two kinds, 

 viz. one situated at the bottom of deep, broad, conical depres- 

 sions, which vary in size, depth, and distance apart, and the 

 other for the most part small, circular, and on the surface ; both 

 also communicating with the " hollow spaces" in the general 

 structure of the wall, which will be more particularly mentioned 

 presently ; surface of the cloaca pierced generally with pores 

 and sparsely echinated ; echinating rays most abundant round 

 the holes leading into the liollow spaces of the wall. Struc- 

 ture of the wall, which in some of the large specimens exceeds 

 an inch in thickness, composed of vermiculated tissue, con- 

 sisting of tortuously branched and anastomosing tubulation, 

 which may be divided into two kinds, viz. that which is more 



