82 



diminish in number and size on the caudal pedicle. Colors — 

 Body and head orange, paler below ; a very few irregularly 

 scattered black spots on the body ; lips brown ; dorsal, anal and 

 caudal fins with the outer half dusky ; pectorals orange at the 

 base, pale yellow on the outer margin, with a black median band, 

 broader superiorly ; gill-opening black, with an occasional milk- 

 white spot ; nasal papillae and tips of the body spines black. 



The species described above belongs to Section ii. B. of 

 Dr. Cxunthers' Catalogue, it measures ten and thi'ee-fourths inches, 

 and was obtained in the Shoalhaven District. 



ON A FRESH WATER ALUA AT WEST MAITLAND 

 W^ATERWORKS. 



By T. WHITELEGGt;. 



Lreological Survey Bi'auch, 



;3 1st July, l^UO. 

 The Acting Curator, Australian Museum. 



Sir, — I have already forwarded to you a sample of 

 the minute vegetable organism, which has of late spread with 

 such alarming rapidity through the main reservoir and the settling 

 tanks at the West Maitland Waterwoi'ks. 



The engineer in charge, Mr. Nicholson, informed me that he 

 was obliged to keep men constantly employed in removing this 

 vegetable growth, as unless kept constantly in check it chokes the 

 supply pipes and obstructs the percolation of water through the 

 tilter beds. The plant appears to me, upon microscojaic examina- 

 tion, to be a variety of fresh-water Alga, but as I am quite 

 unable to otier any suggestions as to the best means for its 

 eradication, I ventured to forward you the samjales of this Alga, 

 in the hope perhaps that you might consider the matter of 

 sufficient importance to have a thorough investigation made to 

 determine (1) the nature of the Alga, and (2) the best specifics 

 for checking or entirely preventing its growth. Mr. Nich olson, 

 the engineer in charge of the Waterworks at West MaUland, 

 would be pleased to furnish any details you may require with 

 regard to the occurrence of the Alga. 



The discovery of an efficient remedy for this pest would be a 

 great public benefit. 



I have the honor to be, Sir, 



Your Obedient Servant, 



(Signed) T. W. E. David, 

 Actg. Ceol. Surveyor in charge. 



