432 Chronicles of Science. [July? 



land, which has at first sight very much the aspect of the African Pro- 

 topterus or South American Lepidosiren. The Queensland fish is, 

 however, larger than Lepidosiren, measuring nearly 5 feet in length. 

 A further examination of the photographs sent hy Mr. Kreffc shows 

 that the fins, which are long worm-like appendages in Lepidosiren, 

 with a very slight border of fin-rays, are here much more developed, 

 being broader and flat, with a large axial lobe and diverging rays, 

 something like those of Polypterus. The scales are large and solid- 

 looking — to judge by the picture — and with a wave-like sculpture on 

 the surface, recalling the palaeozoic Holoptychius in this respect, as 

 well as in the long-lobed fin. The photographs of the skull display 

 a most formidable array of long, wedge-shaped teeth, with undulat- 

 ing edges, exceedingly like those of the Carboniferous Ceratodus. 

 The teeth are, in their limited number and position, very similar to 

 those of Lepidosiren, but have even a more marked resemblance to 

 Ceratodus than have the latter. Mr. Kreft was so struck with the 

 resemblance to Ceratodus that he has proposed to call this mar- 

 vellous fish, which he places with amphibians, Ceratodus Forsteri, 

 after the gentleman who discovered it. The name Potamothauma 

 has, however, been also proposed, since we have no right to rele- 

 gate it to an extinct genus solely on the ground of agreement in 

 the teeth. It is impossible to exaggerate the importance of this 

 discovery with reference to the problems of the geographical distri- 

 bution of organisms, and the ancient relations of land and water. 

 On the other hand, this fish has an equal interest from the purely 

 zoological point of view. We believe that specimens are not very 

 difficult to obtain, so that some may soon be expected in this country. 

 How is it that no one has yet studied the development of Lepidosiren ? 

 Surely, now that in three-quarters of the globe such a fish has been 

 found, the eggs and fry may be expected to be made known. It is 

 only quite recently that the development of Polypterus — the Granoid 

 of the Nile — has been studied on the banks of its habitation, and 

 the fact that it commences life with large external gills like those 

 of a young Newt, or of a very young Tadpole, clearly established. 



The Graphic Method in Odontology. — The study of teeth, not 

 from the dentist's but from the naturalist's point of view, is of very 

 great importance, since by the power of drawing correct inferences 

 from a few teeth we are able to arrive at most weighty conclusions 

 as to the age of Tertiary and other strata. The study of teeth, par- 

 ticularly of mammalian teeth, has become quite a speciality — a little 

 field of knowledge requiring great care and perception of form for 

 its successful cultivation, and standing apart from other anatomical 

 work. So great is the amount of attention required in this study, 

 and so great the importance attached to it, that the late Dr. 

 Falconer occupied most of his life with the study of the teeth 01 

 Elephas, Mastodon, and Ehinoceros ; whilst a fellow of the Eoyal 



