1004 Microscopical Society of London. 



May 21, 1845. J. S. Bowerbank, Esq., F.R.S., in the chair. 



A paper was read by Mr. J. Quekett, " On the structure of the Fla- 

 bella of some of the higher forms of Crustacea, with some remarks 

 on their probable use in the function of respiration." The author 

 commenced his paper by describing briefly the different forms of the 

 respiratory apparatus met with in the lower orders of Crustacea, and 

 then entered more at length into the structure of the branchiae of 

 some of the higher forms, such as the common crabs and lobsters, in 

 the former of which he stated that the proper branchiae were seven in 

 number on each side, and that each branchia was composed of a 

 septum, on two sides of which were arranged numerous lamellae or 

 plates of a quadrangular figure ; on the upper and outer edge of each 

 lamella was developed a hook or spine ; the flabella or sweepers con- 

 sisted, in most cases, of a horny flat filament, with numerous 

 hairs attached to its edges and to its under surface as well : and on 

 an examination, by the microscope, of these hairs, they were found 

 to be scimetar-shaped ; and numerous large hooks and short bristly 

 hairs, all of which were inclined backwards, were developed on their 

 convex edge. And it having been denied by Dr. Milne-Edwards and 

 others, that the use of the flabella was that of causing currents of 

 water to pass through the branchial chamber, Mr. Quekett was in- 

 duced to believe, from his investigation, that the true use of these 

 organs was that of separating the branchial laminae one from the 

 other, so that the water might readily penetrate between them, the 

 arrangement of the spines on the hairs, and on the branchial lami- 

 nae as well, being such as to produce this movement when the hooks 

 on the hairs came into contact with those on the branchial laminae. 



Mr, Powell exhibited and described a newly- constructed portable 

 microscope, it is contained in a case 8f inches long, 5j inches wide, 

 2 inches deep, possessing rack and fine adjustments to the optical 

 parts ; ^ inch of motion to the stage, in rectangular directions, with 

 \ inch, J inch and 1 inch object-glasses, forceps and animalcule-cage : 

 higher powers may be added, as it is sufficiently free from tremor to 

 bear the highest that are made. 



A letter was read from Mr. T. Boys, giving a description of his 

 method of mounting objects in Canada balsam, by which he is ena- 

 bled to avoid air-bubbles. Having provided a small, single- wick oil 

 lamp with a chimney, slips and thin pieces of glass, nippers, a 

 pointed iron wire, in a wooden handle, and some of the clearest 

 Canada balsam, diluted with the best spirits of turpentine to a con- 

 sistency to allow it to drop readily from the point of the wire ; a slip 



