REPORT ON THE POLYZOA. 17 



(4) Horner a foliacea, Macgillivray. 



Hcn-nera fuUaeea, Maogilliv., Proc. Eoy. Soc. Vict., vol. ix., p. 142, 1868. 



Rdihornera foliacea, Busk, Brit. Mus. Cat., pt. iii., p. 19, pi. xiii. figs. 1, 2, and pL xix. ; Haswell. 

 ? Retihornera dentata, ? Retihornera plicata, Kirchenpauer. 



Character. — Zoarium expanded, foliaceous, irregularly plicate or convoluted, rising 

 from a short stem with a discoid base ; main branches straight, parallel, connected by 

 numerous transverse ceUiferous branches or trabeculae, forming quadrangular fenestrae of 

 pretty uniform size, from 07 to 2 mm. in length by O'S to 0-4 mm. wide, or about the width 

 of the branches. Zooecia in the young state exserted, with a usually bifid or toothed 

 orifice, about 0'05 mm. in diameter. In the older condition more immersed, with an 

 irregularly bifid or toothed, thickened, somewhat expanded orifice. Anterior surface 

 fibro-reticulate, obscurely punctate and uneven ; posterior sulcate, granular, obscurely 

 punctured or pitted. Ooecia subglobose, dorsal ; usually three zooecia in the width of a 

 branch, and one in a trabecula. 



Habitat.— ^t&tion 161, off Port Phillip, 33 fathoms, sand. Station 163b, off Port 

 Jackson, .35 to 38 fathoms, rock. 



[South Australia, Gould, Macgillivray, Queensland, Haswell.] 



Although at one time inclined to regard the fenestrate form of Hornera as entitled 

 to the rank of a distinct genus or subgenus, I no longer regard it as forming more than a 

 subgenus, as in all essential characters it perfectly agrees with such forms as Hornera 

 lichenoides, Hornera frondiculata, and Hornera cmspitosa, Mihi., differing as do 

 those species from Hornera vidacea in having the anterior aspect fibro-reticulate, and 

 the ooecia dorsal. In the Brit. Mus. Cat, pt. iii., p. 19, I have described Hornera 

 foliacea as being furnished with delicate spiculse projecting from the sides of the 

 fenestras, but it is highly probable that these are merely the spiculse of some parasitic 

 encrusting Sponge ; in aU other respects the form brought by Mr. Gould from 

 South Australia in my collection, from which the account in the Brit. Mus. Cat. was 

 drawn up, exactly agrees with the specimens in the Challenger collection, which again 

 are undoubtedly the Hornera foliacea of Mr. Macgillivray. In one of the specimens 

 is a shallow, circular, cup-shaped depression on the dorsal aspect, doubtless the remjaht 

 of an ooecium, but these organs would appear to be very rare. 



(ZOOL. CHALL. EXP. — PAET u — 1886.) Ddd 3 



