1(3 Art. 1.— N. Annandale and T. Kawamura : 



In a series of many hundred specimens only two were found that 

 contained these bodies and both of these were taken in a single 

 haul of the net. 



If only Phase III were to be considered, there can be no 

 doubt that $. dementis would have to be regarded as a very distinct 

 species closely allied to the species belonging to the genera Pachy- 

 dictyum Weltner from Celebes and Gortispongilla Annandale from 

 Palestine, both of which it resembles in its compact form, large 

 and conspicuous oscula and unusually spacious and well-developed 

 exhalant system. We have not, indeed, seen any specimen in 

 which the central cavity connected with this system is so large 

 or so regular as it appears to be in the only known species of 

 Pachydictyum, while the skeletal cortex characteristic of Corti- 

 spongilla is either altogether absent or else represented by mere 

 rudiments possibly not at all homologous. These rudiments consist 

 of the interdigitating ridges to which a reference has been made 

 above. Their skeletal support is consolidated in a manner 

 strongly suggestive of the external consolidation of the skeleton 

 that takes place in the Palestinian genus, and their frequent 

 absence may be due in part to erosion of the surface of the sponge — 

 a phenomenon also manifested in Gortispongilla. The peculiarities 

 of this phase of S. dementis are, moreover, correlated with the fact 

 that the sponge lives in comparatively deep water, attached to hard 

 objects of small size (if it is attached at all), and on a bottom 

 composed of sand or tine gravel, the particles of which are liable 

 to be carried into its interior and can only be voided with great 

 difficulty. The conditions also enter into the environment in 

 which Gortispongilla is found, and probably occur in that of the 

 habitat of Pachydictyum, of which nothing very precise is known. 

 Notwithstanding, however, the apparent strong differentiation of 

 the Phase III of S. dementis we have found some specimens in 

 fairly deep water that are exactly intermediate between it and 

 Phase II, and we can not correlate any differences in the structure 

 of the skeleton or the form of the spicules with the differences 

 usually so conspicuous in the extermal characters. 



Phase II roughly corresponds with the specimens on which 



