324 THE PROCEEDINGS OF THE LINNEAN SOCIETY 



which, in the large posterior teeth, is represented by a slightly- 

 elevated longitudinal line.* This longitudinal line is more or 

 less distinctly visible in H. PhilUpi, according to the individual. 

 Now, if we suppose this median longitudinal line on the pos- 

 terior teeth developed into the form of a cutting edge or crest, 

 we obtain some idea of the chief peculiarity of the dentition of 

 H. galeatus. 



The figures 30 and 31 are accurately drawn, with the aid of 

 compasses, from a shrivelled, and not quite perfect pair of jaws 

 preserved (labelled only with the name of the locality — Broken 

 Bay) in the Macleay-Museum. 



As the jaws are in the meantime preserved in the Museum as 

 " unique," I have been unable to use them to obtain a transverse 

 section of the large teeth. 



The only perfect specimen of H. galeatus in Sydney at present 

 is one in the Australian Museum, and as it is a stuffed specimen, 

 one could merely see the anterior teeth, and only with some 

 trouble get a glimpse of the crest of the posterior teeth. Mr. E. 

 P. Ramsay had the kindness (for which I here express my gra- 

 titude) at my request to order the jaws to be taken out from the 

 stuffed specimen. The stuffed museum-specimen has been in no 

 wise injured by this, and the museum has thereby acquired a 

 valuable anatomical preparation. Both jaws are in excellent 

 preservation ; and I am thus placed in a position to give a more 

 complete description of the teeth** than I could otherwise have 

 given. 



I do so chiefly because the form of the teeth of H. galeatus, so 

 far as I am aware, has not yet been described.*** ' 



• " C6te longitudinal," of Agassiz. Poissons fossiles. Lome III., page 83. 

 " I regret that I have only received this second jaw of H. galeatus after all the plates 

 for this paper were prepared, so that I could not exchange figures 30 and 31 which only 

 shew a part of the jaws, for a comi)lete drawing of the well-preserved preparation in the 

 Australian Museum. But although figs. 31 and 32 only shew a single horizontal row of 

 teeth (the jaws from which the drawings were taken not being perfect), yet they give a 

 correct notion of the form of the sequence of the rows, and of the number of the teeth 

 (in a horizontal row). The curve of the row (figs. 30 and 31) is, however, only approxi- 

 mately correct ; the preparation, which served as the original of my sketch, was so un- 

 symmetrically shrivelled up that it permitted me to copy only the form of the teeth and 

 the arrangement of the rows, and not the shape of the jaws. 



*** In the description of H. galeatan by Dr. GUnther (Catalogue of Fishes, vol. 1., 

 p. 416) there is nothing said about the teeth. 



