PORIFERA OF THE L.M.B.C. DISTRICT. PAIL 
to them. Their chief character is: they are filled up by 
strongly light-refracting clear granules, the diameter of 
which I estimate to be 0:0006 mm. From their position 
and appearance I scarcely doubt that those cells are the 
skeleton-forming elements (scleroblasts), and the appear- 
ance suggests that these granules represent anabolic stages 
in the formation of the siliceous material for building up 
the spicules. However, developing spicules were never 
seen inside those cells. 
Apparently the same structures have been figured by 
Oscar Schmidt* in Halisarca guttula, 8., Spongia adri- 
atica, 8., and Spongelea elegans, 5S. He describes them as 
irregular, mostly spindle-shaped bands of sarcode, with 
delicate processes, full of molecular granules, but without 
cell membrane, nucleus or nucleolus. He gives the fol- 
lowing resumé about the nature of these structures: ‘‘ Die 
sehr allgemein bei den Spongien vorkommenden Korner- 
ballen, welche oft regelmassig und dicht geschichtet er- 
scheinen und nicht selten mit einem helleren Centralfleck 
versehen sind, sind weder nach ihrer Entstehung noch 
nach ihren Bestandtheilen als gemeine Zellen aufzufassen. 
Sie sind ein Product oder Derivat der Sarcode, und da 
ich die Kornchen bei keinem Schwamme vermuisste, ein 
mehr oder weniger wesentlicher Bestandtheil dieser Sub- 
stanz.” Notwithstanding Schmidt’s views I cannot help 
regarding those structures as true cells. To call them 
** Product oder Derivat der Sarcode”’ is no satisfactory 
explanation from the standpoint of modern histology. 
Similar cells have been figured by Ridley and Dendy + 
in Aeinella (?) paradova, which in the explanation of the 
* Osear Schmidt, ‘‘ Supplement der Spongien des Adriatischen Meere 
enthaltend Histologie,” &c,, p 3, pl. i., figs. 6—11. 
+ Ridley and Dendy, ‘‘ Report on the Monaxonida, collected by HeM.S 
‘Challenger,’” pl. xlix., fig. 2a. 
