^6 Descriptions of New, 



characteristic mark is the great development of the avicu- 

 laria. These are situated on much elevated, cell-like 

 processes ; they are shortly and broadly spatulate ; the 

 mandible is peculiar in its structure, the lower half (as seen 

 in situ without decalcification or staining) being differentiated 

 from the rest by a thick, chitinous hoop. 



Family Tubulipoeid^. 

 Stomatopora geminata, n. sp. PI. II., fig. 3. 



Zoarium branched ; branches obscurely concentrically 

 rugose ; surface with numerous brown, white-bordered 

 puncta. Zooecia separated by shallow sulci, opening in pairs 

 or triplets ; mouths projecting, turned rectangularly forward, 

 and closely united together laterally throughout their length. 



Port Phillip Heads, Mr. J. B. Wilson. 



At once distinguished from all the other species by the 

 arrangement of the cells in pairs or triplets, with the free 

 oral extremities united laterally, and turned rectangularly 

 forward. 



Biastopora cristata, n. sp. PL II., fig. 1. 



Zoarium either encrusting and with portions raised into 

 bilaminate lobes, or wholly bilaminate, the laminse parted 

 by a thin calcareous septum, the margin of which is produced 

 beyond the zooecia to form a crest-like ridge. Zooecia 

 opening on both sides of the lobes ; crowded, free for a 

 considerable extent; immersed portions separated by shallow 

 grooves ; surface closely and finely punctate, except the free 

 part, which is smooth or obscurely ringed ; mouth circular 

 or oblique. Ooecium a large inflation of the zoarium. 



Port Phillip Heads, Mr. J. B. Wilson. 



In the figured specimen the zoarium consists of a single 

 layer, closely surrounding a branched mass of the calcareous 

 tubes of a small annelid, from the free-growing edge of 

 which in parts extends the margin of a thin calcareous 

 basal lamina. From various parts of the encrusting layer 

 spring small bilaminate lobes, the laminse of which are 

 separated by a thin calcareous septum (identical with the 

 basal plate of the encrusting part), the edge of which pro- 

 jects in a crest-like manner beyond the zooecia. In another 



