ISODICTYA. 121 



inches broad, and one and a half inch thick, with ten 

 large, elevated, oscular orifices, the largest nearly a 

 quarter of an inch in diameter. On the paper accom- 

 panying the specimen the colour is stated to be 

 ' lilac,' and Mr. Norman adds, ' I have a specimen, 

 not so fine as regards oscula, &c.j but twice the size 

 of this.' I am not surprised in so large a specimen at 

 the congregation of the oscula in large cloacal organs. 

 This frequently occurs in other largely- developed 

 species of sponge, which in a younger state have the 

 oscula simple and dispersed on the dermal surface. 

 In Halichondria panicea these differences are of fre- 

 quent occurrence." 



17. ISODIOTYA VAEIANS, BoW., II, 281 ; III, 307, PI. 



XL VIII, figs. 14—16, PI. LXXXVIII. 



1867 Philotia varians. Gray. Proc. Zool. Soc, p. 522. 



18, ISODICTTA ELEGANS, Bow., II, 283 J III, PL XLIX, 



figs. 1 — 6. 



Habitat. — Under stones between tide-marks. West- 

 port, Roundstone, and Birterbuy Bays ; also dredged 

 in these same bays growing on shells and Nullipora 

 (N.). 



19. IsODIOTYA PALLAX, BoW., II, 302 ; III, PI. LI, figs. 



10—18. 



