34 ON SOME POLYZOA FROM THE QTJEENSLAND COAST, 



these the present communication is an account; Nearly all the 

 specimens were obtained with the dredge in a single spot close to 

 Holborn Island, an islet situated about twenty miles to the north- 

 east of Port Denison, and about forty to the westward of the 

 G-reat Barrier Eeef . Here the bottom at a depth of about twenty 

 fathoms seemed to be covered with little else than numerous kinds 

 oiPolyzoa, intermixed with species oiPlumulariidce and Sertulariidce 

 and a few shells. Many of the Pohj%oa are massive branching 

 forms, which, judging from the contents of the dredge and hempen 

 tangles, seem to grow here in great profusion, and are no doubt 

 in the act of forming by their gradual growth and decay more or 

 less extensive deposits analogous to the Polyzoa-beds characteristic 

 of the tertiary formations of South Australia and Europe. It 

 would be interesting to determine the extent of this remarkable 

 bed : bad weather prevented us doing anj^thing in this direction ; 

 it is unusual to dredge Pohjzoa in abundance at so slight a depth, 

 but no doubt the sheltering influence of the Great Barrier is a 

 sufficient explanation,^'' and it is not unlikely that a similar growth 

 may occur commonly within the Barrier at like depths, in situations 

 where the set of the current does not favour the deposition of 

 coral mud from the reefs. 



I regret having been unable to obtain in Sydney some of the 

 the works bearing on the present subject ; I have particularly to 

 regret the want of D'Orbigny's ' ' Paleontologie Frangaise," 

 Hagenow's ^'Bryozoen der Maestrichten Kreidebild," and the 

 " Natural History Eeview," the volume of which for 1858 contains 

 descriptions of various Australian Polyzoa by Prof. Sir Wyville 

 Thomson. 



Unless otherwise particularised the habitat of the species is 

 Holborn Island, 20 fathoms. 



* A similar abundance of Bryozoa has been recently noticed at a depth of 40 

 fathoms in the Mediterranean ; vide " On the Bryozoa of the Bay of 

 Naples," by A. W. Waters, F.G.S., Ann. and Mag., Nat. Hist. (5) III. 

 p. 280. 



