June 1, 1868.] 



HARDWICKE'S SCIENCE-GOSSIP. 



12; 



entertaining pages in Ivirby and Spence's Ento- 

 mology, under the head of "The Motions of In- 

 sects," bearing on it. These, however, are mainly 

 occupied with the detail of facts proving, what is 

 now admitted, that they rise into and float through 

 the air by means of their webs. Only one sug- 

 gestion is made which appears to approach the 

 explanation of the power by which this is done; 

 for that it is effected by "magic," or by "some 

 subtle electric influence," may be passed by. The 

 suggestion is that it may be caused by the emission 

 of a current of air. This from so small a creature, 

 without a suitable apparatus, seems impossible; 

 but that the air has something to do with it is not 

 so unlikely. The downward rush of numerous 

 threads from all the spinnerets at once against the 

 current of air, steadied and in some measure aided 

 by the contact of the floating web, is presumed to 

 be the motive power which throws the spider for- 

 ward "like a flash," or with less speed in propor- 

 tion to the force exerted. The [application of a 

 similar power in another element is seen in the 

 larva of the dragon-fly ; and most are familiar with 

 the flight of the sky-rocket, which mounts with 

 astonishing force by the downward impulse of the 

 escaping gases. The web is a loose structure, and, 

 even where thinnest, is made up of numerous 

 threads, having no coherence; like an untwisted 

 skein of worsted, it is easily flattened or distended, 

 as it often is, probably by the exertions of the 

 insect, and so made more buoyant. 



If there be any truth in this explanation, it is due 

 to the power and definition of our modern micro- 

 scopes, of which the higher powers must be used. 

 Many vain speculations would be saved' if the 

 organs by which any wonder is effected were first 

 carefully examined. It is hoped that some further 

 observations on this difficult subject will be made, 

 and recorded in Science-Gossip. S. S. 



NEW INFUSORIA* 

 By J. G. Tatem. 



IT is hoped that a few short notices of some of 

 the rarer species of Infusoria, either hitherto 

 unrecognized as indigenes, or so seldom met with 

 as to be presumably uuknown to the great majority 

 of microscopists, if accompanied by accurate draw- 

 ings, would not be unacceptable to the members of 

 the Quekett Club. 



It is to be regretted that the living creatures 

 cannot themselves be exhibited. These "rari 

 nantes gurgite vasto," however diligently searched 

 for, are not usually obtainable in numbers, and are 

 still less readily procurable just when they may 

 be desired. I cannot, therefore, expect that an 



* Read at the Quekett Microscopical Club, March 27, 1868. 



opportunity of submitting any of them to your 

 examination will be afforded. The drawings, how- 

 ever, taken from the objects themselves by means 

 of the neutral-tint reflector, with the utmost atten- 

 tion to accuracy of outline and completeness of 

 detail, will, I trust, serve to convey a sufficiently 

 correct idea of them. 



I. Chcetospira Mutter i, " found hitherto in the 

 open cells of torn leaves of Lemna trisulca, growing 

 in fresh water near Berlin," is occasionally obtained 

 from the ponds and ditches of this neighbourhood 

 (Reading), but so far as my observations extend, 

 it selects in preference those of the frond and rootlet 

 of Lemna minor. The flask-shaped sheath is wholly 

 immersed within the frond, the internal cell-walls 

 of which are broken down to afford it the required 

 accommodation, and secure the animal, in addition 

 to its own horny sheath, the further protection of 

 the cuticle of the plant. The ciliated feather-like 

 spire alone projects, and when fully extended makes 

 a complete turn. The terminal cilium is somewhat 

 the longest. A small opening, presumably the oral 

 orifice, may be detected at the base of the spire. 



Fig. 115. Chcttospira M'dlleri x 380. 



Though mostly solitary, more than one is some- 

 times found in the same frond. On one occasion a 

 group of five small specimens was met with, lodged 



