Zoology.'] NATURAL HISTORY OF VICTORIA. \_Polyxoa. 



Port Phillip Heads. 



This species is not uncommon at Port Phillip Heads, and is 

 found growing on Adeonella and allied polyzoa. The zoai'ium 

 attains a height of three-fourths of an inch, and is simple or more 

 usually branched. The zooecia are very much confused, flask- 

 shaped, oblique or erect, the surface smooth, rough or pitted. 

 It is extremely difficult to see the primary mouth, owing to the 

 rapid development of the peristome. It is lofty, with a sinus in 

 the lower \\^. The peristome is produced into a long, nearly 

 cylindrical tube, carrying a horizontal avicularium on one side, 

 situated on the summit of a minute semi-spiral tube. The 

 avicularium seems to be originally situated at the sides of the 

 primary mouth immediately after the commencement of the 

 development of the peristome, and, as the peristome grows, it is 

 carried upwards in a semi-spiral manner. This oral avicularium 

 is frequently absent. In some specimens there are numerous 

 large, spatulate, vicarious avicularia. The ooecium is very 

 peculiar, being situated below the mouth, and the front being 

 deficient in calcareous matter and closed by a convex, lens- 

 shaped, thick, chitinous membrane. This membrane is smooth 

 or faintly perforated or, when older, occasionally sub-calcareous 

 and cribriform. 



EXFLA.NATION OF FlQURES. 



Plate 156. — Fig. 4, branch of an Adeonella with several zoaria of Lehythopora growing on 

 it, natural size. Fig. 5, another zoariura, natural size. Fig. 5a, portion of the same, magnified, 

 showing zooecia with peristomes and ooecia. Fig. 5b, lateral view of single zooecium from the 

 same, showing the peristome, semi-spiral aviculiferous tube, and profile of ocecium. Fig. 5c, 

 another zooecium, to show the shape of the membranous front of the ooecium. Fig. 6, orifice of 

 peristome from another specimen, with the oral avicularium. Fig. 7, primary mouth, seen 

 vertically. Fig. 8, outline of a peristome, with avicularium and top of tube. Fig. 9, to show 

 the commencement of formation of an ocecium. Fig. 10, an operculum. 



Plate 156, Figs. 11-13. 



PCECILOPORA ANOMOLA (McG.). 



[Genus PCECILOPORA (McG.). (Sub-kingdom Mollusca. Class Polyzoa. Order 

 Infuudibulata. Sub-order Cheilostomata. Family Celleporida;.) 



Ge)i. Char. — Zoarium erect, bilaminate, branched. Zooecia indistinct ; primary month 

 with a sinus in lower lip ; peristome commencing as an elevated point with a small avicularium 

 on the summit, finally becoming a tumid, sub-circular ring. Ooecia immersed, covered by a 

 perforated plate.] 



Vol. II.-DBOiDB XVI.-21. [ 211 ] 



