BY E. F. KALLMANN. 309 



merely an unevenness due to the presence, close below the cor- 

 tex, of occasional, rather large grains of sand, etc. ; whal 

 other inequalities of the surface there are, appear to be the 

 result rather of irregularity of growth than of any definite 

 tendency or habit of growth. Oscula, or openings resembling 

 oscula, were observed only in the complete specimen ; they are 

 situated in two small groups, and in each group are closely 

 arranged, and of variable diameter up to 2-5mm. The canals 

 traversing the sponge are comparatively few in proportion to 

 its mass, and at most only about 1mm. in diameter. 



(The following brief account of the minute anatomy is in- 

 tended mainly only as a guide to the identification of the 

 species. A fuller description is necessary, but is scarcely pos- 

 sible with the material at my disposal, the condition of preser- 

 vation of which, after nearly thirty years in spirit, leaves 

 much to be desired.). 



The cortex is without fibrous tissue, and consists of a kind 

 of chondrenchyma. The mesogloea is very extensively deve- 

 loped and characterised by a peculiar vesicular structure due 

 to numerous very distinctly outlined, apparently empty, oval 

 cells (cystencytes), which are arranged in clusters rather than 

 uniformly distributed, and measure 15/x to liO/x in diameter. 

 There is no proper skeleton, nor anything of the nature of 

 connective tissue fibres. The chamber-system appears to be 

 eurypylous. The flagellated chambers vary in shape, from 

 oval to nearly spherical ; in the type-specimen, presumably 

 owing to contraction, they are very seldom much more than 

 30 /x (yet may attain to 40 /x) in diameter ; but in the other spe- 

 cimen {Eeniera collectrix)^ they are usually between 35 and 

 40 /x in diameter, while a certain few, which are more elongated 

 and relatively narrower than the others, measure 45 by 30 

 to 35 /x. Inside most (if not all) of the smaller canals, lying in 

 contact with, or in close proximity to, their wall, there occur 

 a variable number of irregularly rounded cells, measuring 10 

 to 12/x in diameter; the nature of these is not clear, but pos- 

 sibly they are algae. 



