SIGMATELLA. 201 



0-2 millim. wide originate, which are provided with anuular strictures. These 

 are themselves branched, but do not appear to give off secondary ramifica- 

 tions. They supply direct the ciliated chambers, which are 0*07 millim. long 

 and about 0-04 millim. broad. The exhalant canals are about as wide as the 

 inhalants, and join to form larger stems, which open out into the large and 

 conspicuous oscular tubes. These are curved and tortuous in the massive and 

 lobose varieties, but appear straight and radiating from the base to the 

 marginally situated oscula in S. c. flahellmn and serrata. Only in S. c. elegans 

 the oscula are small and inconspicuous. 



Carter states that Spongiopharja pottsii occurs in his Dysidea Tcirlcii. Although 

 I have often found filaments in sponges with an arenaceous skeleton somewhat 

 similar to that of Sirjmatella, I have never found them in any true Spongelid. 



The ciliated chambers of all the sponges which contain filaments are small, 

 spherical, pyriform; and probably Carter had true Hirciniao before him. 

 Symbiotic oscillarians are also recorded by Carter in the same sponge. He 

 compares them to the oscillarians discovered by P. E. Schulze, where they 

 already occur in the embryo, and confounds them, by an oversight, with the 

 filaments. 



Sigmatella corticata, var, papillosa, Marshall. 



Dysidea argentea, W. Marshall, " TJeber Dysideiden und Phoriospongien 

 Zeitschrift fiir wissenschaftliche Zoologie, Band xxxv. Seite 107 (1880). 



Dysidea callosa, W. Marshall, I. c. p. 104. 



Dysidea favosa, W. Marshall, I. c. p. 98. 



Dysidea favosa, S. 0. Eidley, " Spongida:" Eeport on the Zoological Collections 

 made in the Indo-Pacific Ocean during the Voyage of H.M.S. ' Alert,' 

 p. 388 (1884). 



Dysidea gramdosa, H. J. Carter, " Supplementary Eeport on the Specimens 

 dredged up from the Gulf of Manaar," Annals and Magazine of Natural 

 History, ser. 5, vol. vii. p. 376 (1881). 



Dysidea Tcirhii (partim), H. J. Carter, I. c. p. 374. 



Dysidea Jcirhii (partim), H. J, Carter, " Description of Sponges from the Neigh- 

 bourhood of Port Phillip Heads, South Australia," Annals and Magazine 

 of Natural History, ser. 5, vol. xv. p. 216 (1885). 



Holojjsamma laminafavosa (partim), H. J. Carter, I. c. p. 212. 



Spongelia IcirJci, A. Hyatt, " Eevision of the North-American Poriferse. — 

 Part II.," Memoirs of the Boston Society, vol. ii. p. 539 (1877). 



Irregularly massive incrusting sponges, which are when young horizontally 

 expanded, cake-shaped, and attached by a broad base. Larger specimens 

 appear erect, and possess irregular, lobose, or even digitate tortuous processes, 

 which rise from the upper surface to a varying height. These may coalesce 



