204 



HARDWICKE'S SCIENCE-GOSSIP. 



[Sept. 1, 1S70. 



them in mead, it gives that drink a very agreeable 

 aroma and taste. "Mead-sweet" is one of its pro- 

 vincial names. I wonder if this refers to land on 

 which the flower grows, or to its ancient use in 

 mead-making ? 



The Toad-flax is a flower I gather in September, 

 — the "butter and eggs" of childhood's "floral find- 

 ings." It seems to me there are more yellow blos- 

 soms in autumn than in any other season of the year, 

 from the Golden Rod and Great Mullein down to 

 the Tansy. 



Upper Norwood. Helen E. Watney. 



MACROTHRIX. 

 By Edwin Smith, M.A. 



IEOUND, in July last, a good many examples 

 of this curious little entomostracan in the so- 

 called " Black Water," a shallow pool on the turfy 



Fig. 1Q5. Macrothrix magnified. 



soil of Lindow Common, near "Wilmslow, Cheshire. 



It belongs to the family of the Daphniadae, and 

 bears a close general resemblance to an ordinary 

 Daphnia. My specimens corresponded in then- 

 leading characters to the description of Macrothrix 

 laticornis given by Baird in his British Entomos- 

 traca. Thus, referring to the figure drawn from an 

 average specimen of my capture, we observe that 

 the superior antennae are flat, and hang by a joint 

 from the prominent beak. At their free extremity, 

 which is broad and straight-edged, I noticed three 

 minute and three larger bristles or spines. The 

 inferior antennas are of considerable size, and divide 

 into two branches. The posterior branch has three- 

 terminal feathered setae or bristles, and a short 

 spine at their base. A second short spine occurs 

 at the end of the first joiut. Baird mentions four 

 setae on this particular branch; three in the position 

 stated, and another from the end of the second 

 joint. But I could not detect this fourth seta with 

 the most careful search on any of my specimens. 

 I have therefore not drawn it. The anterior branch 

 of the inferior antennae is armed with five seta?, 

 three terminal feathered ones accompanied by a 

 small spine at their base, one at the end of the 

 second joint, and a third much longer than the rest 

 serrated with minute spines at the end of the first 

 joint, also having a minute spine at their base. 

 Each seta is itself jointed about the middle, and it 

 is only the outer tapering segment which is feathered 

 or distinctly spinous. The creature has, moreover, 

 a large compound eye, in front of which is situated 

 an oblong black spot. The intestine is strongly 

 bent into three deep curves, but is not convoluted. 

 The last segment of the body has two hooked 

 spines at its extremity, and a pair of long bristles 

 further back at an angle of the segment in question. 

 The carapace is oblong, somewhat blunt behind, 

 and armed on its anterior margin with long bristles. 

 Its surface, in my specimens, was distinctly dotted. 

 Its general form was longer in proportion to the 

 breadth than Baird's figure of Macrothrix laticornis 

 (tab. xv. 2). Can I have lit upen a new variety? 

 The absence of the fourth seta on the posterior 

 branch of the inferior antenna? is also note- 

 worthy, as another point of difference from Baird's 

 description. 



While comparing my completed drawing with 

 the original contained in the live-box, what was my 

 astonishment to observe some of the parts suddenly 

 become double ! There first appeared a double 

 hinder segment, with a double set of hooked 

 spines. Then a double beak and double superior 

 antennae showed themselves. Then other parts 

 were doubled in like manner ; and it became evident 

 that I was the fortunate witness of the moulting- 

 process, if that is the correct term. The little 

 creature was " shuffling off its mortal coil," in pre- 

 paration for a new stage of growth. I immediately 

 mounted my interesting friend in glycerine, hoping 



