160 SUMMARY OF CURRENT RESEARCHES RELATING TO 



lakes and ponds. The first part of his elaborate and instructive paper 

 now published deals with the morphology. Taking as type Gosse's 

 published figure of A. cochlearis, the author shows how the form varies 

 in three or four definite directions, which he calls respectively : — 

 (1) Macracantlia-typica-tecta series, (2) hispida series, (3) irregularis 

 series, and (4) robusta group, after the names the several varieties have 

 received by different authors. With an elaborate table of measurements 

 he shows how the animal as a whole, and particularly the posterior 

 spine, increase and decrease in size ; a table of 100 measured individuals 

 of the first series is given, varying in total size from 271 yx to 96 /a, and 

 the posterior spine from 100 /x to 0, the last being identical with Gosse's 

 A. tecta. A plate with 27 figures illustrates the cycle of variation. 

 A discussion of the probable causes of these variations is promised 

 in the second part of this paper, to be published shortly. 



Rotatoria of the United States.* — In connection with the work of 

 the U.S. Commission of Fisheries, Mr. H. S. Jennings has published an 

 interesting list, with critical notes, of all species of rotifers, 246 in 

 number, hitherto found in the United States, with special reference to 

 those found by him in the great lakes. Two species, Notops pelagicus 

 and Pleurotrocha parasitica, are described as new. As a general result 

 of his investigation the author formulates the conclusion that the Rota- 

 toria are potentially cosmopolitan, any given species occurring wherever 

 on the earth the conditions necessary to its existence occur. In stagnant 

 swamps all over the world are likely to be found the characteristic 

 rotifers of stagnant water, with little regard to the country in which the 

 swamp is found; in clear lake water will be found everywhere the 

 characteristic limnetic Rotifera ; in Sphagnum swamps everywhere the 

 Sphagnum or Moss Rotifera. Variation in the rotifer fauna of different 

 countries is probably due to variation in the conditions of existence in 

 the waters of those countries, not to any difficulty in passing from one 

 region to another. 



In the introduction the author gives a word of warning against the 

 senseless abuse of naming species by those who, through want of experi- 

 ence or knowledge of what is known, fail to recognise the fact that they 

 are not in a position to publish names of new species ; such work he 

 describes as a positive injury to science and a nuisance to all careful 

 scientific students. It is to be hoped that everyone wishing to describe 

 a new species of rotifer will learn by heart and inwardly digest this 

 sentence. 



Rotifers of New Zealand.f— Mr. F. W. Hilgendorf has published 

 a " Contribution " on this subject, which comes under Mr. Jennings' 

 recent designation of a positive " injury to science and nuisance to all 

 careful scientific students." The author succeeded in finding sixteen 

 6pecies of rotifers, twelve of which he describes as new. Half of these 

 new species can at once be recognised as old acquaintances, and the 

 other half are of no value, and scarcely recognisable as rotifers. The 

 figures of the four plates bear about the same relation to rotifers as the 

 wooden blocks in a child's Noah's ark have to the animals they pretend 



* U.S. Fish Commission Bulletin for 1899 (1900) pp. 67-104 (9 pis.), 

 t Trans. New Zealand Inst., xxxi. (1898) pp. 107-34 (4 pis.). 



