Zoology.'] NATURAL HISTORY OF VICTORIA. [Pohjzoa. 



epitheca, and marked in the same manner as the zocecia. In a few 

 of the zooecia there is a single large avicularium situated at the 

 upper angle. 



Explanation or Figure. 

 Plate 138. — Fig. 5, portion of specimen, magnified ; avicularia are shown in two of the 

 zooecia. 



Plate 138, Figs. 6, 7. 

 SCHIZOPORELLA RIDLEYI (McG.). 



Description. — Zoarium encrusting'. Zocecia rhomboidal or elongated, in 

 radiating linear series, separated by slightly raised margins ; surface wben young- 

 smooth, when older deeply areolated at the edges ; mouth semicircular above, 

 straight below, with a small rounded sinus. Below the mouth a small, vertical, 

 elliptical avicularium on an elevated part of the zocecium. Ocecium rounded. 



Reference. — P. H. MacGillivray, Trans. Roy. Soc. Vict., Oct. 1882; S. 

 marsupktm, Ridley, Proc. Zool. Soc. Lond., Jan. 1881. 



Port Phillip Heads. 



In young specimens the mouth, with its semicircular upper 

 margin and straight lower lip with rounded sinus, is well seen, as 

 well as the small, elliptical, sub-oral avicularium, situated on the 

 raised semilunar portion of the zooecium. In older and more 

 calcified zocecia this raised portion frequently becomes so developed 

 as to obscure the view of the mouth and avicularium ; in these 

 also there is usually a series of deep grooves converging from the 

 margin to the raised sub-oral portion. 



Explanation of Figures. 



Plate 138. — Fig. 6, group of young zooecia, to show the form of the mouth and situation 

 of sub-oral avicularium. Fig. 7, portion of an older specimen, showing the converging grooves 

 and ooecia. 



Plate 138, Fig. 8. 



SCHIZOPORELLA ARACHNOIDES (McG.). 



Description. — Zoarium encrusting. Zocecia oval, distinct, convex, smooth; 

 mouth arched above, with a deep, rounded sinus in the straight lower lip; a series 

 of (usually) seven stiff spines, several of which, especially the lower, are situated at 



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