PREFACE. 



each with its complete descriptive letterpress, will be published, of 

 such illustrations as are ready, without systematic order or waiting 

 for the completion of any one branch. The many good observers 

 in the country will thus have the means of accurately identifying 

 various natural ol)jects, their observations on which, if recorded and 

 sent to the National ]\Iuseum, where the originals of all the figures 

 and descriptions are preserved, will be duly acknowledged, and 

 vdW materially help in the preparation of the final systematic volimie 

 to be published for each class when it approaches completion. 



This seventh Decade gives detailed figures and descriptions in 

 the first two plates of those most interesting molluscs, the Argo- 

 nauts, as represented by one of the species occurring in some 

 sunmiers not uncommonly in our bay, and in which the rare chance 

 of finding the Cuttlefish in its so-called Paper-Nautilus Shell has 

 been taken advantage of to give details which will be welcome to 

 scientific men at home as well as here. 



The third plate shows the characters of the new Australian 

 blue-spotted Eagle-Ray, or Sting-Ray, not figured before. 



The fourth plate illustrates one of the large and formidable 

 Sharks ( Odontaspis)^ the terror of bathers, not uncoiumon in our 

 bay, and also the new Australian Tope, a smaller Shark, or Dogfishj 

 formerly confounded with the English Tope, and not figured before. 



The fifth plate illustrates one of those curious forms intermediate 

 between Pipe-fishes and the Sea-horses, named Phyllopteryx^ or 

 Leafy Sea-di'agons ; also our commonest httle species of Sea-horse, 

 not fio;ured before. 



The next three plates continue the illustrations of om' native 

 Polyzoa, for the contribution of which to the National Museum and 

 this work I am indebted to Dr. MacGillivray. 



The ninth and tenth plates give figures for the first time of two 

 magnificent new species of those gigantic Insects of the Phasma 

 group, in which Australia is so rich, and the resemblance of which, 



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