6 NATURAL SCIENCE. Jan.. 



The Square-Mouthed Rhinoceros. 



It has been considered that the square-mouthed, or so-called 

 White Rhinoceros (R. siiitiis) is already extinct. Recently, however, 

 Mr. F. C. Selous has written to our contemporary, the Field, to say 

 that a few of these magnificent animals still survive in a remote corner 

 of Mashonaland. One of these last survivors has already been killed, 

 with the view that its remains should find their way to the British 

 Museum. We trust, however, that the authorities in Mashonaland 

 will take care that the others are not molested, and may be allowed a 

 chance of propagating their species. 



We may take this opportunity of mentioning that although most 

 zoologists have recognised the extreme specialisation of the molar 

 teeth of this species, as exemplified by their very tall crowns, and the 

 flat plane of wear of their grinding-surfaces, yet it does not appear to 

 have been noticed that they differ from those of all other living 

 Rhinoceroses by the presence of a thick investing coat of cement. 

 Not only does this cover the outer surface of the tooth, but it likewise 

 fills up both the main and the posterior valleys. Indeed, the molars 

 of this species bear almost the same relationship to those of the 

 Sumatran Rhinoceros as is presented by the molars of the Horse to 

 those of the Anchithere. 



In the extinct Woolly Rhinoceros (R. antiquitatis) the cement is 

 present to a less degree in the molar teeth, which are of the same 

 general structure ; while in the allied R. platyvhinus, of the Siwalik 

 Hills of India, there was, probably, also a certain amount of this 

 constituent. In both these extinct species the teeth do not, however, 

 appear to attain the extreme specialisation of the square-mouthed 

 Rhinoceros, and it is accordingly difficult to regard the latter as 

 representing a genus apart from the one including all the other 

 existing species, which we should otherwise have been disposed 

 to do. 



The Science of Growth. 



Readers of a recent article in Natural Science on the Anatomy 

 and Development of the Brachiopoda, who were appalled by certain 

 strange and fearful words, such as " nepionic," " ephebolic," and 

 " nostologic," will be interested to learn that those terms have just 

 been elucidated and improved by S. S. Buckman and F. A. Bather 

 in a paper entitled " The Terms of Auxology " [Zoologischev Anzeiger, 

 November 14 and 28, 1892, pp. 420 and 429). Growth and change, 

 as the authors observe, do not stop in an animal when the embryonic 

 stage has been passed ; nor is the study of later stages of less impor- 

 tance than that of the earlier. Thus has arisen a new science, of 

 which embryology is only a part ; and, as was inevitable, definite 

 names have been given to the various post-embryonic stages. Un- 

 fortunately, the names used were not only open to serious objection 



