Spcvges from South Aiisfralia. 47 



Fam. 4. Pachastrellida. 



" Char. Without cortex ; densely spiculifevous, even to 

 stony hardness ; structure confused ; no fibre." 



When I use the word "confused" it must be understood 

 that the structure is so only apparently, for there is nothing- 

 confused in Nature, wherein all is harmony, and everything 

 has its place. 



With reference to the two groups of this family, viz. 17 

 and 18, respectively named Pachastrellina and Lithistina, I 

 have nothing to add beyond what is stated in my original 

 classification (Z. c. pp. 185 to 187), the wliole of which " classi- 

 fication was chiefly compiled to facilitate a description and 

 location of the sponges dredged by ILM.S. 'Porcupine' 

 ('Annals,' 1876, vol. xviii. p. 220), where, at pp.406 to 410, 

 some new species of Pachastrella will be found, together with 

 that from Japan, described in the ' Annals ' of 1885 (vol. xv. 

 p. 403). Of new species of the group Lithistina I had, with 

 the exception of what is stated in the 'Annals' of 1873^ 

 vol. xii. pp. 437-444, and 1876, vol. xviii. pp. 460-468, no 

 communication to make until 1880, when ray report on the 

 specimens from the Gulf of Manaar &c. was published 

 ('Annals,' vols, v., vi., and vii., pp. 437, 35, and 361), 

 wherein at p. 142, pis. vii. and viii., and p. 372, pi. xviii. 

 vols. vi. and vii., several will be found described and 

 illustrated, together with the mode of development of the 

 skeletal spicule which these; young and perfect specimens 

 enabled me to follow satisfactorily, so that in Discodermia it 

 was easy to see that the most complex form of the tetracti- 

 nellid, skeletal spicule originated in the simple nail-like disk 

 of the surface, which, when not more than l-300^7^ inch in 

 diameter .^ presents the quadrijid canal that characterizes the 

 fully developed tetractinellid form. Lastly, this was again 

 observed in the large and fresh specimen of Racodiscula aste- 

 roides from Japan, which I described and illustrated in the 

 ' Annals' of 1885 (vol. xv. p. 400, pi. xiv. fig. 11). 



Fam. 5. Potamospongida, 



" Char. Fragile sponges bearing seed-like bodies or stato- 

 blasts and inhabiting freshwater." 



For my division of the " then known species" of the sponges 

 to be included in this family and their history generally, see 

 my paper in the 'Annals ' of 1881 (vol. vii. pp. 77 to 107, 

 pis. V. and vi.). It has been contended that my " characters " 

 of this family are incomplete, seeing that no seed-like bodies 

 (gemmules or statoblasts) have yet been found in Uruguaya 

 corallicides, Bk., or in Lxibomirskia Imicalensis^ Dybowski ; 



