SCYPHIDIÜM LONGISPINA. 27 



be distinguished as hypogastralia. There exist no pentactins under 

 the layer. 



In tlie two large specimens in hand, both being torn oÔ' at base, 

 the basidictyonalia can not be observed. I have therefore examined 

 one of the two young individuals for those characteristically 

 ankylosed sj)icules, and actually found them in the basal region 

 of the little sponge growing on a prostal needle. This was at 

 the place directly invested by a thin and small-meshed siliceous 

 reticulum, the basal-plate of F. E. Schulze, over which was a 

 layer of irregularly distributed hexactins, the basidictyonalia. 

 These are small but thick-rayed, with uneven surface. They are 

 in fusion not only with the basal-plate but also here and there 

 with themselves, in a manner similar to the condition seen in 

 fig. 12, PI. XXI. The mode of their occurrence on a spicule 

 of another individual reminds me of the small basidictyonal masses 

 I have found in Slauroealypius fjlaher {cfr. Contrib. I., p. 18G, 

 foot-note). 



The hexasters are of the following three types : 

 1. Oxyhexaster. This occurs in great abundance in the 

 choanosome as well as in the subdermal space. Especially numer- 

 ous is it near the gastral surface and in the gastral layer itself. 

 It is not uncommon to see several attached to the proximal ray 

 of the gastralia, as if they had been shifted on from below along 

 it. Diametei-, 100-122 !>■. The principals are always exceedingly 

 short, so that the bases of terminals are situated close to the 

 somewhat swollen central node. The terminals are obsoletely 

 rough-surfoced. As to their number and the degree of their 

 development, there exists a certain difierence between the oxy- 



