I. DESCRIPTION OF THE SPECIES COLLECTED BY THE 



"ALBATROSS." 



Erylidae. 



Tetraxonia with rhabd and teloelade megascleres, and a superficial armour 

 composed of aspidasters ^ and microrhabds. Euasters are always present in the 

 choanosome. 



Sollas ^ divided the family Geodidae (Geodiadae) of Gray ^ into the two 

 subfamilies Erylina and Geodina, and placed the geodid genera Erylus, Caminus, 

 and Pachymatisma in the former. Later authors, I* among others, have not 

 retained these subfamilies and have placed the three genera named, together 

 with the typical genus Geodia and its allies, in the family Geodidae. The 

 genera Caminus and Pachymatisma are not represented in the collections of the 

 "Albatross, " so that I have not been able to give any new data concerning their 

 systematic position during this work. The genus Erylus on the other hand is 

 well represented, and the examination of the "Albatross" material has shown 

 that, as I have already stated in the first part of this monograph (ante p. 17), 

 Erylus differs very considerably from Geodia the typical genus of the Geodidae. 

 I therefore now not only revert to Sollas's (loc. cit.) original pro])osition of divid- 

 ing the family Geodidae into two subfamilies but propose to go even farther and 

 to place Erylus in a separate family: the EryUdae. 



The question whether other genera (Pachymatisma, Caminus) should also 

 be placed in this new family I shall not, for the reason given above, discuss here, 

 and I leave them, for the present at least, in the Geodidae; the description of 



' The aspidasters are those spicules of the Erylidae which were previously termed sterrasters. 

 They are distinguished from the sterrasters of the true Geodidae by passing, during their development, 

 through a stage with jjerfectly smooth surface which does not occur in tlie development of the sterr- 

 asters of Geodia and its allies, and also by their flattened, disc-like shape. 



2 W. J. Sollas. Tetractinellida. Rept. voy. " Challenger," 1888, 25, p. cxlvii. 



^ J. E. Gray. Notes on the arrangement of sponges. . . .Proc. Zool- soc. London, 1867, p. 492. 



* R. V. Lendenfeld. Tetraxonia. Tierreich, 1903, 19, p. 84, 



267 



