382 HALF-HOURS AT THE MICROSCOPE. 



the differences do not seem to me greater than may be explained 

 by supposing the pieces of skin to have come from different parts 

 of fish of the same kind. It is of essential importance, in feeling 

 our way to exact knowledge, that every step should be made sure. 

 I wish very much to see longitudinal and transverse sections of 

 these scales, with the skin in which they are implanted, as well as 

 thin sections made parallel with the plane of the tooth-like 

 portion. This will bring out some very interesting points and 

 show how marvellously like teeth they are, both in conformation 

 and in structure. The fish drawn on this Plate (with the hope of 

 ascertaining if it be of the same species with that from which the 

 scales were taken) was a great favourite with me when on a visit 

 to the Boulogne Aquarium. It lay on a ledge of rock, absolutely 

 without motion, all the time its portrait was being taken, and was 

 a very handsome fellow, but with '■'■such a wicked eye" like you see 

 in the portraits of Napoleon Trois. What looks like a projecting 

 tusk is but a fold of skin which hangs down on either side of the 

 mouth — a sort of feeler, in fact. These fish were not uncommon 

 in the Boulogne market ; some reached a length of three feet and 

 upwards. I was informed by the keeper of the aquarium that 

 their French name was " Roussette." 



Transverse Section of Human Molar (PI. XXIV., Fig. 13) is 

 described in the explanation to the plate. Will some member 

 illustrate for us the structure of human teeth in their various forms 

 by vertical and horizontal sections ? Then follow it up by sections 

 of pachydermatous teeth — rodent, carnivorous, lacertine, piscine, 

 etc. They would form an endless series of beautiful and instruc- 

 tive objects, especially if fossil teeth were included, and would be 

 most interesting. Tuffen West. 



There has been established in Berlin a People's Society for 

 Natural Science, the chief object of which is to offer scientific 

 lectures that will be interesting to those having no technical know- 

 ledge of the subject. The first lecture before the Society was given 

 by Di. Forster, Director of the Royal Observatory, and entitled 

 "Conditions and Beginnings of Life on the Earth." — Science. 



