STAUROCALYPTÜS GL ABER. 211 



basidictyonalia belonging to quite young individuals of the species : 

 it appears that a brood of the young had temporarily or otherwise 

 settled themselves on, and had each formed its own basidictyonal 

 framework around, the parenchymalia of the old specimen in 

 question. It is impossible to do more than speculate as to the 

 mode of origin of that brood of the young. But one point appears 

 to me to be almost certain, viz., that the reticular bodies treated 

 of are the same as those described by F. E. Schulze ('99, p. 

 64 ; PI. XIV, figs. 2-6) from the l)uds borne on the prostalia 

 lateralia of Rhabdocalyptus mirabilis. Seen in this light and from 

 my point of view concerning the phylogenetic relation between 

 the " Lyssacina " and the " Dictyonalia " (Contrib. III., pp. 23- 

 25, foot-note), it seems to me readily explicable, if, in the de- 

 velopment of a firmly seated lyssaciue Hexactinellid, certain sup- 

 porting spicules early underment ankylosis and thus acquired a 

 dictyonine character. 



But to return to the general characters of the species. 

 Summarily speaking, w^e have here to do with thick-walled, sac- 

 cular or vase-like, firmly seated forms, which, after attaining a 

 certain size, are laterally compressed to a greater or less degree. 

 Superiorly the wall somewhat closes in towards the sharp, but 

 not thin, oscular edge. The young are ovoid in shape and are 

 furnished with conspicuous, but slender and isolated prostal needles, 

 which, after the full growth of individuals, seem to become 

 entirely or almost entirely lost. Pentactinic prostalia do not 

 occur in any stage of the life. 



The dermal surface is moderately smooth. The delicate 

 ectosomal skeleton consists of a minutely quadrate-meshed dermal 

 lacew^ork and of supporting hypodermal strands. The latter are 



