Zoology] NATURAL HISTORY OF VICTORIA. [Polyzoa. 



prominent, in older specimens nearly globose. The surface is 

 smooth or pitted, the pits occasionally, near the mouth, giving an 

 obscurely ribbed appearance. The peristome forms a thin rim, 

 with occasionally a prominence on each side, on the summit of 

 which is an oval or broadly elliptical avicularium, the mandible 

 directed upwards and outwards. 



Explanation of Figures. 



Plate 148. — Fig. 3, two zooecia from the growing edge. Fig. 3a, two zoceeia, with growing 

 and mature ocecia. Fig. 3b, vertical view of zooecium to show the mouth. 



Plate 148, Figs. 5-6. 



CELLEPORA COSTAZEi, var. (Audouin). 



Description. — Zoarium encrusting". Zoceeia ovate, smooth, irregularly ar- 

 ranged, confused; mouth wide, with a broad rounded sinus in the lower lip; usually 

 a prominent mucro below the mouth, supporting a small avicularium and occasionally 

 an aviculiferous process from the peristome on one or both sides. Numerous 

 scattered avicularia, some very large, with broadly expanded spatulate mandibles. 

 Ocecia of moderate size, with a rounded or mitriform area, bounded by a distinct, / 

 raised margin, pitted or sculptured in a radiate manner. 



References. — P. H. MacGillivray, Trans. Roy. Soc. Vict., 1884; typical form, 

 Hincks, Brit. Mar. Pol., p. 411, pi. 55, figs. 11-14; typical form, C. Hassallii, 

 Busk, Brit. Mus. Cat. Mar. Pol., pt. ii. p. 86, pi. cix., figs. 4-6. 



Port Phillip Heads. 



There may be some doubt as to the identification of this with 

 the European species. It differs in the general absence of the 

 elevated avicularia on the sides of the mouth, which are only 

 occasionally found on one side. In an English specimen, however, 

 they are also absent in many of the zooecia. The sub-oral mucro 

 is also generally wanting in English specimens. The vicarious 

 avicularia are also larger in the Australian form. I had at first 

 intended to describe it as a new species under the name of 

 C. spatula, which may be retained as that of the variety. 



Explanation of Figures. 



Plate 148.— Fig. 5, portion of specimen, magnified. Fig. 6, portion of another specimen. 

 Fig. 6a, ocecia of same. Fig. 66, single zooecium, with avicularium on high process. 



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