Zoology.-] NATURAL HISTORY OF VICTORIA. IPolyzoa. 



munita it occasionally ends in a sharp spine, while in umbonata it 

 ends at the base of a large sharp umbo. All intermediate forms 

 may be observed. The general form of the operculum is similar, 

 although somewhat modified in the different forms. In the typical 

 form it is thinner, and constantly presents a peculiar dendroid 

 marking, which also occasionally occurs in sinuata, but not in the 

 others. The peculiar large, jointed spines seem to be confined to 

 the typical form (including var. sinuata) and umbonata; at least 

 I have not seen them in the munita form. 



The different varieties may be all grouped under three Forms or 

 Sub-species : — 



Form monilifera (P. McG.). 



Plate 96, Fig. 1-3. 



Description. — Potyzoary expanded, foliaceous, closely plicated, usually much 

 broader than high; fenestras rounded or elliptical, much narrower than the inter- 

 spaces ; mouth at first with the lower margin entire or with a slight notch ; as 

 growth advances, the peristome of the lower lip is much produced, retaining a narrow 

 notch, at one angle of which a small avicularium is situated; ovicells prominent, the 

 beaded line broad, the extension upwards slightly clavate, and extending nearly to 

 the upper edge. 



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

 Mr. Watts. 



This common form is confined to shallow water. On the frame- 

 work of the wooden pier at Queenscliff it forms large masses, 

 almost dry at low tide. The mode of growth is characteristic. 

 The polyzoary is closely plicated, forming numerous, narrow calycles 

 and cavities, expanding widely from its attachment and, sometimes, 

 either from a single zoarium or the confluence of several, forming 

 masses 6-9 inches wide and 2-4 or 5 high. In the youngest 

 marginal cells the shape of the mouth varies, the lower edge being 

 straight, hollowed, with a small central sinus, or with a deep lateral 

 one. As growth advances a narrow central sinus is formed in the 

 peristome. On one angle of this a small avicularium is usually 

 developed. Occasionally this angle is much produced forwards, 

 bearing the avicularium on its summit. Sometimes the angles of 

 the sinus coalesce, leaving a rounded foramen, and occasionally this 



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