Zoology.] NATURAL HISTORY OF VICTORIA. [Polyzoa. 



Plate 118, Figs. 1 to 5. 



HORNERA FOLIACEA (P. McGL). 



[Genus HORNERA (Lamx.). (Sub-kingd. Mollusca. Class Polyzoa. Order Infundi- 

 bulata. Sub-order Cyclostomata. Family Idmoneidse.) 



Gen. Char. — Zoarium brancbed, branches distinct, anastomosing or connected by transverse 

 bars. Zocecia distinct, opening irregularly on one side of the branches. Ooecia dorsal or 

 anterior. ] 



Description. — Zoarium rising- from a discoid base, forming- a foliaceous ex- 

 pansion, composed of sub-parallel brandies dichotomously divided and connected 

 by transverse bars forming oblong- fenestra ; anterior surface divided into elongated, 

 more or less rhomboidal, spaces by the approximation, at intervals, of slightly 

 elevated longitudinal ridges ; zocecia opening in these spaces, exserted, the peristome 

 produced and lacerated especially on the expanded outer lip; posterior surface 

 longitudinally sulcate, the elevations between the sulci transversely marked by 

 shallow grooves. Ooecia very large, bulging, extending usually over several 

 branches, deeply and closely pitted. 



Reference. — Homera foliacea, P. H. MacGillivray, Tr. Roy. Soc Vict. = 

 Retihomera foliacea, Busk, Brit. Mus. Cat., Marine Polyzoa, Part iii., p. 19, pi. 

 xiii., figs. 1 and 2, pi. xix. 



Port Phillip Heads ; Portland, Mr. Maplestone ; Western Port 

 and Sealers' Cove, Baron von Mueller. 



This beautiful and common species rises from a discoid base, 

 spreads usually at first in a flabelliform manner, but ultimately 

 becomes more or less convoluted, and frequently attains a size of 

 two inches. The fenestras are oblong, varying considerably in size 

 according to age, sometimes narrower than the branches, sometimes 

 as wide or even wider. The zocecia are exserted in perfect specimens, 

 with the peristome lacerated ; in those at the margins of the 

 branches the outer lip is much expanded, forming a laciniated lip 

 with usually two or three teeth. There are seldom more than 

 two or three rows of zocecia in a branch, and their occurrence on 

 the cross-bars is very infrequent. The surface of the branches 

 is faintly granular and traversed by longitudinal, slightly elevated 

 ridges, the approximation of which, at intervals, forms eloDgated, 

 irregular, somewhat rhomboidal spaces in which the orifices of the 

 cells are situated. The posterior surface is longitudinally sulcate, 

 the intermediate elevations being marked by close transverse 

 furrows. The depth of the posterior sulci, the distinctness of the 



Vol. II.— Decade XII.— m. '71 



