REPORT ON THE POLYZOA. 
17 
(4) Hornera foliaceci, Macgillivray. 
Hornera foliacea, Macgilliv., Proc. Roy. Soc. Yict., vol. is., p. 142, 1868. 
Retihornera foliacea , Bask, Brit. Mus. Cat., pt. iii., p. 19, pi. siii. figs. 1, 2, and pi. xix. ; Haswell. 
? Retihornera dentata, l 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 celliferous branches or trabeculae, forming quadrangular fenestrae of 
pretty uniform size, from 07 to 2 mm. in length by 0'3 to 0’4 mm. wide, or about the width 
of the branches. Zocecia 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. — Station 161, off Port Philip, 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 ccespitosa, mihi., differing as do 
those species from Hornera violacea in having the anterior aspect fibro-reticulate, and 
the ocecia dorsal. In the Brit. Mus. Cat., pt. iii., p. 19, I have described Hornera 
foliacea as being furnished with delicate spiculae projecting from the sides of the 
fenestrae, but it is highly probable that these are merely the spiculse of some parasitic 
encrusting Sponge ; in all 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 remnant 
of an ooecium, but these organs would appear to be very rare. 
(ZOOL. CHALL. EXP. PART L. 1886.) 
Ddd 3 
