112 



HARDWICKE'S SCJENCE-G OSSIP. 



them ; by using rings of varying thickness, the 

 trough can be made a large or a small one at 

 will. When examining a very small quantity of 

 water, I have used thick blotting-paper, cut into a 

 semicircular form, in place of an indiarubber ring. 

 The trough is made water-tight by being placed 

 between two plates of vulcanite, 3 in. by ij in. by 

 1 in. thick. The plates are bound together by three 

 brass screws with milled h( ads ; the screws serve to 

 keep the glass slips in position when placed between 

 the plates ; by tightening the screws, the plates are 

 made to press evenly on the slips, which in turn 

 press firmly on the indiarubber between them, and 

 thus a water-tight trough is at once formed. \Vhen 

 It is necessary to clean it, all that is required is to 

 loosen the screws, pull out the slips, separate and 

 dry them, replace the indiarubber and the slips in 

 position, and screw up again. A semicircular part 

 is cut out of the vulcanite plates to allow the glass 

 trough to be visible. It is very neat in appearance, 

 and its production is a step in the right direction, as 

 "there is so little glass about it to get broken, or brass 

 to get tarnished. It can also be used as a coarse com- 

 pressorium. — J. Campbell Christie, Ilaniiltoti, A\B. 



Failure in Mounting.— A few days back I 

 •attempted to mount a portion of a frog's ovary for the 

 microscope. I examined the ova on a slide with a 

 drop of water, and their structure was clearly dis- 

 played. Lacking a certain knowledge as to what was 

 'the best medium to mount them in, I placed a portion 

 •of the ovary in glycerine for two days and then 

 mounted it in the same, but on ex.iniination I found 

 that the structure of the ova was all but destroyed, and 

 that the germinal spots had turned to a dark brown 

 colour and seemed much distorted in shape. Can any 

 of your readers inform me the reason of my failure ? 

 Did I employ the wrong medium, or must it have been 

 some defect in the manner of mounting ? — //. Fox. 



GiciSTES Janus. —At a recent meeting of the 

 East Kent Natural History Society, Mr. Rosseter 

 exhibited a Melicerta he had obtained from a pond 

 in this neighbourhood. On examining it we found that 

 it was not one of the usual sort of Melicerta we had 

 been accustomed to find hereabouts, and we were at 

 a. loss to make it out, never having seen just such 

 XI one before. Whilst we were consulting about it, 

 Colonel Horsleycame in with the February "Journal 

 of the Royal Microscopical Society," and in that was a 

 description of a new rotifer, with drawing of tlie same, 

 ■discovered by Mr. J. Hood of Dundee in the Loch 

 Lundie in September of last year, which appears to 

 answer exactly tckthat exhibited by Mr. Rosseter. No 

 doubt we shall be able to procure from the same 

 pond more specimens, when I shall be able to 

 ■examine them with greater care and to compare 

 ^notes with the account in the Journal. It is there 

 ■named CEcistes Jatuts. — James FuUagar. 



The Skeleton Wheel-bearer (Ceratophyllum"^. 

 — Examining some Rotifera, collected during the 

 month of January and kept in a separate vessel, I 

 found a Ceratophyllum, or skeleton wheel-bearer, 

 fig. 75. It will be observed by those who are acquainted 

 with this beautiful and rare rotifer that it is in a few 

 particulars differently constructed from its usual re- 

 presentation in drawings or in other living specimens 

 I have seen. If any of your 

 .■';'^';:!',ri;«'.;, readers who may possess 



" Ponds and Ditches " will 

 refer to page 170, and will 

 compare with my sketch, they 

 will perceive the different pe- 

 culiarities. The spines spring- 

 ing from the first joint of the 

 tail, a, are turned towards the 

 head of the creature and not 

 towards the extremity of the 

 tail, as usually represented. 

 The shoulders of the sheath, 

 b, are rounded, not pointed. 

 These two differences in the 

 creature lead me to suppose 

 that it is another species of 

 Ceratophyllum. The three 

 joints, c, fit into each other 

 like draw tubes. It is not 

 only amusing, but a wonderful 

 sight, to see the creature draw 

 them up, bring the long spines, 

 d, that are attached to the last 

 joint, well forward, fix them securely to the glass, 

 and then by a violent effort jerk itself forward and 

 then lie motionless, as if enjoying the act of pro- 

 pulsion. Being a good swimmer, it reminded me 

 of the pleasure one derives from back-swimming after 

 drawing up the legs and propelling oneself forward — 

 how delightful the sensation is of travelling through 

 the water in this position. The sheath of the creature 

 is very strongly ribbed, e, and the creature can pro- 

 trude or withdraw itself at pleasure. — T. B. Rosseter, 

 Canterbury. 



Quekett MiCROSConcAL Club. — The March 

 publication of the above club contains the following 

 valuable papers : " On certain Immature forms of 

 Diatomacea?," by C. C. Karop, M.R.C.S. "On a 

 Method of Dry Mounting for opaque Objects," by 

 Mr. H. J. Roper. "On mounting opaque Objects 

 with Bees-w-ax," by Mr. H. Morland. "On the 

 Use of Arabin in mounting Microscopical Objects," 

 by H. J. Waddington. "On a simple Growing- 

 slide," by T. Charles White, M.R.C.S. (President). 

 " On some Desmids new to Britain in 1880," by 

 M. C. Cooke, M.A., LL.D., F.L.S., " On a new 

 Vivarium," by J. D. Hardy, &c. Mr. H. J. Wadding- 

 ton, in his paper " On^the Use of Arabin in Mounting 

 Microscopical Objects," gives the following method 



Fig- 75.— Skeleton Wheel- 

 Bearer (Ceratophyllum). 



