Zoology.-\ NATURAL HISTORY OF VICTORIA. iPohjzoa. 



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

 ends at the base of a large sharj:) 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 umhonata; at least 

 I have not seen them in the munita form. 



The difiPerent varieties may be all grouped under three Forms or 

 Sub-species : — 



Form monilifera (P. McG.). 



Plate 96, Fig. 1-3. 



Description. — Polj-zoary expanded, foliaceous, closely plicated, usually much 

 broader than liig-li ; fenestra? rounded or elliptical, much narrower than the inter- 

 spaces ; mouth at first with the lower marj^-in entire or with a slig'ht notch ; as 

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

 notcli, 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 edg-e. 



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 Queenscliflf 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 <i(}i^(^ being 

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

 one. As growth advances a narroAv 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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