HARDWICKE'S SCIENCE-GOSSIP. 



231 



attendant particles of dust which are absorbed in, 

 and which mark its outline and course. A remark- 

 able instance occurred recently, May, 1879, in which 

 such a whirlwind, formed almost instantaneously, 

 ripped away the entire roof of a house, the surround- 

 ing air being quite still at the time. 



I have watched from a distance of a few yards 

 a small cyclone of this character, in which the 

 dust, so absorbed, revolved with intense rapidity, 

 while the atmosphere around was perfectly calm. 

 This was on a hot summer day. The presence of 

 such currents of air among the clouds may account 

 for some of the more remarkable forms which these 

 occasionally assume. 



MICROSCOPY. 



EUGLENA VIRIDIS AND ITS BULBED FLAGELLUM. 

 — In Mr. F. Jas. George's communication of August 

 1st, number one sketch certainly resembles a 

 Euglena of some sort, but does not show flagellum 

 with bulbous termination. The second and third 

 sketches represent a widely different organism. 

 Unless the transitional stages are watched unre- 

 mittingly, the mere fact of one organism succeeding 



; Fig. 178. — Euglena viridis, showing the bulbed dagellum.' 



or taking the place of another cannot be accepted as 

 a veritable metamorphosis, and Euglena viridis still 

 remains on the border line between the animal and 

 vegetable kingdom. I enclose sketch by Mr. G. 

 Harkus, showing three of the protean forms commonly 

 assumed by E. viridis, and swelling or bulb with which 

 the flagellum ends (Ross J-in. Beyepiece + 380). These 

 may be of interest, as I at all events have not met an 

 observer who has previously noted this peculiarity. 

 — M. H. Robson, Neii'caslle-iipon-Tyne. 



Mandibles of" Ants worn by Use. — An as- 

 sertion having been made at the Boston Natural 

 History Society by the Rev. H. C. McCook that the 

 mandibles of ants become blunted, and are even 

 worn off by use, a microscopical examination of about 

 one hundred specimens of Pasimachus has taken 

 place before the society, when it was seen that all the 

 fresh specimens had perfectly shaped and sharp 

 mandibles, whilst those specimens which were old 

 and worn-looking presented every gradation of 

 bluntness of the mandibles. 



The Quekett Microscopical Club.— No. 40 

 of the Journal of this well-known Microscopical 

 Society contains the following papers: — "On the 

 Urticating threads of Actinia parasitica,' 1 '' by F. A^ 

 Bedwell ; "On the Rotifers, by dark field illumina- 

 tion," by C. T. Hudson ; " On the Micro-Megascope," 

 by Dr. John Matthews ; and on "The Dual-Lichen 

 Hypothesis," Dr. M. C. Cooke. The last paper is a 

 thorough and unanswerable demolition of the theory 

 of Schwendener that lichens are only so many algo- 

 fungi. Nobody was so capable of dealing with this 

 subject as Dr. Cooke, and nobody could have done it 

 so well. 



New Species of Entomostraca. — At the recent 

 meeting of the British Association, Sir John Lubbock 

 called attention to the occurrence in England of 

 Leptodora hyalina, a very interesting crustacean 

 found in the deep Swiss lakes, subsequently in those 

 of Switzerland, Russia, and Italy, and recently found 

 by Messrs. T. Bolton and H. E. Forrest in the Olton 

 reservoir, near Birmingham, though not in any 

 streams or shallow waters. Like many marine 

 organisms it is as transparent as glass — a peculiarity 

 which is of advantage to vegetable feeders, as 

 rendering them less conspicuous to their foes, and to 

 predaceous species by enabling them to steal un- 

 suspected on their victims. The anterior antennae 

 are peculiarly developed in the males, but quite small 

 in the female. It has been a question whether these 

 organs are for hearing or smelling. The latter seems 

 most probable ; where one sex attracts the other by 

 sound, both sexes have the ear well developed. Of 

 course the sex attracted must have a good ear in 

 order to distinguish the sound ; but so also must the 

 singing sex, in order to regulate the sound. Hence 

 in such cases we do not find any marked difference 

 between the auditory organ in the male and female. 

 But with smell the case is different. The scent is a 

 specific characteristic, and is not regulated or modified 

 by the will of the individual. Hence, when one sex 

 attracts the other, it is not necessary that the attract- 

 ive sex should have well-developed organs of smell. 

 Hence Weismann concludes that in leptodora the 

 anterior antenna, being much more highly developed 

 in the male than in the female, are organs of smell. 

 After describing some other curious points in its 

 anatomy, Sir John observed that like other animals 

 of the same group, leptodora lay two kinds of eggs — 

 one sort in summer, which hatch rapidly, and a 

 second in autumn which are provided with a thick 

 coat and remain undeveloped through the winter, 

 hatching only when the warm weather returns. It is 

 a most curious and interesting fact that, as Muller 

 observed, these two eggs produce young which are 

 quite unlike one another. In our common Daphnia 

 the young at first are quite unlike their parents, 

 having only three pairs of appendages, and being in 

 what is called the "nauplius" stage. Such young 



