PEOaRESS OF MICROSCOPICAL SCIENCE. 77 



an error of omission that they are not given in the first place as an 

 introduction to the student. 



We think Mr. Van Voorst would have done well to have had another 

 editor in addition to the three already selected, and that he would 

 have found him easily in the Eoyal Microscopical Society we have not 

 the slightest doubt — some one who, being constantly at the Society, was 

 well acquainted with the various discoveries which have taken place 

 of late years on the subject of Diatomaceae, et hoc genus omne. And 

 we hope that, if his engagements are not definitively concluded, he 

 will not leave our suggestion without some serious consideration. 



As to the contents of the book there is not much for us to speak 

 about ; but such as there is, is so far well done. We have gone over 

 this part rather carefully, and we find that the authors have not left 

 unnoticed what has been done of late years, some of their references 

 being to books and papers published as late as 1870. We think the 

 new edition, on the whole, a very fair one ; and if the publisher does 

 not absolutely scoff at our advice, we doubt not the future parts will 

 be everything that the working microscopist can desire. 



PROGRESS OF MICROSCOPICAL SCIENCE. 



The Development of Amhlysfoma lurida has been recently worked 

 out by Dr. P. R. Roy, an American natiu-alist. He leaves the develop- 

 ment within the egg unnoticed, as he says there is no difference 

 between it and the fish, which has been carefully studied already. 

 The tadpole of this salamander emerges from the egg in twenty- 

 five days. April 25, length one-half inch, colour olive, eye-spots 

 visible, two short holders, gills rudimentary. May 5, tenth day, eyes 

 developed, irids golden, colour greyish olive, with three faint trans- 

 verse bands of a darker hue, gills plumed, no holders, fore legs 

 starting ; is now active, and feeds voraciously on aquatic insects. 

 May 25, thirty days from the egg, fore feet tridactylous, consisting of 

 thumb, forefinger, which is greatly elongated, and middle finger a 

 little longer than the thumb. If there should be an arrest of develop- 

 ment at this stage, the track would be bird-like. Next, the fourth 

 finger makes its appearance, and, on the hind feet, the fifth comes still 

 later. What is especially interesting is that when the legs or feet 

 have been amputated, which frequently occurs, the operation being 

 performed by those miniature fresh-water sharks, the larvae of dragon- 

 flies and water-beetles, the development of the toes is precisely in the 

 same order, first the three toes, then the fourth, and on the hind feet 

 the fifth. The gills are now beautifully plumed, and when closed 

 reach to the centre of the entire animal ; hind legs starting. June 20, 

 fifty-six days, hind feet developed. As the lungs increase the gills 

 wither and are gradually absorbed, so that by the middle of August 



G 2 



