HARDWICKE'S SCIENCE-GOSSIP. 



57 



already in a dying state, and, being warned from past 

 experience and Pritcliard, that Hydras infested with 

 K. polyporutn die (?), I detemiined to try an experi- 

 ment. I removed one of the Hydras and put it in a 

 thoroughly clean trough ; having placed the trough 

 under the microscope, I found that Hydra was "eaten 

 alive " with K. polyporiim. 



Every other day I gave the Hydra a good bath by 

 laying the trough in a deep saucer filled with water ; 

 refilling the trough with fresh water ; at the end of a 

 fortnight I had materially diminished them. I still 

 continued the bathing, occasionally adding a piece of 

 alsinastrum to draw off the K. polyporitni, which I 

 found very effective. I kept the creature well fed, 

 occasionally giving it a D. piilex, and now as I am 

 writing at the end of five weeks, the creature is alive, 

 in good health, and perfectly free from A", polyporiim. 



Those left in my large zoophyte-trough all suc- 

 cumbed possibly to these parasites, and went the way 

 of all things in nature, and strange to say, K. polyporiim 



Fig. 44. — Kerona polyporiim. 



disappeared too. My experiment went a long way 

 to prove that cleanliness was a great factor in curing 

 Hydra of its troublesome guest. Although //. fiisca 

 is the host of K. polyporiim, yet it is a free swim- 

 ming creature, and is as capable of getting its living 

 that way as crawling over the knotty tentacles and 

 slimy body of H. fusca. I captured a few, and 

 placed them on a glass slip, covering them with a thin 

 covering-glass. It made a capital live-box, leaving 

 them sufficient room to swim about, yet limiting their 

 scope of locomotion. Under the circumstances, I was 

 able to observe and make a sketch of them. Fig . 44 

 represents K. polyporiim as seen crawling over the 

 body or tentacles of //. fusca, and its ventral side, 

 as seen in its free swimming state ; a being the oral 

 aperture through which a stream of fluid passes, the 

 current being sent down by the lashing of the cilia 

 b at the head of the creature. 



This aperture seems to be made up of two valves, 

 opening very slowly, and closing with a sudden snap. 

 In the vacuoles c monads could be plainly seen, under- 

 going the process of digestion. 



Canterbury. T. B. ROSSETER. 



A WEEK'S RAMBLES WITH A HAMMER 

 IN THE ISLE OF WEIGHT. 



By W. W. Watts, B.A. 



[Continued Jf-oin p. 31.] 



ON the third day I started for Headon Hill, 

 intending to work round the hill, as the 

 dry winds had consolidated the pools of mud 

 formed from the Osborne clays and the Middle 

 Headon beds, and it was possible to walk round the 

 whole hill. 



The first thing that struck me on approaching the 

 hill was the westerly dip of the beds, which does 

 not agree with the dip assigned to them in a section 

 published a year ago. The section to be seen at the 

 north end of the hill is much the same as that given 

 for the similar beds in Colwell and Totland Bays. 

 The Bembridge limestone is found at the top, and 

 underneath it the mottled Osborne marls, the whole 

 thickness of which may be seen along the section, 

 showing a fairly well-marked terrace of limestone 

 at one horizon. Below it comes clay, with large 

 specimens of Paliidina knta, and then a thick bed of 

 limestone, which forms a well-marked terrace all round 

 the hill to its outcrop at the southern end. This 

 contains a great number of specimens of Planorbis and 

 Lymn?ea ; then come sands, and then the total thick- 

 ness of the Middle Headon, including (i) a clay band 

 with Ceriihium ventrkosum and C. concavum, which 

 weather out in vast numbers ; (2) a thin freshwater 

 limestone ; (3) the Venus bed with the usual fossils ; 

 (4) numerous clays, and then a limestone with.Limnsea 

 and sands below, which appear to be on just the 

 same horizon as the last exposure of the Warden Cliff 

 sands seen just south of the anticlinal. Below this 

 the section is obscured by a landslip, which repeats 

 the above-mentioned beds, while down on the shore 

 line is a mixture of timber and mud, often with 

 finely-weathered fossils from the various beds above. 

 I carefully traced these beds round the hill, and found 

 them on the fine exposures seen at the southern 

 end, the thick limestone forming so marked a horizon 

 that there was no mistaking the beds. But besides 

 this, the Lower Headon limestone afforded a good 

 horizon, and also the thin freshwater limestone 

 and the Cerithhim ventrkosum bed of the Middle 

 Headon. Among the more important features noticed 

 in passing were : (i) the thin Osborne limestone 

 thickened on the south to a very considerable extent ; 

 (2) the Upper Headon limestone and sands thickened 

 and thinned in an inverse relation, and lignite ap- 

 peared here and there in these beds ; (3) the Ccri- 

 thium concavtim beds in one place formed a bastard 

 limestone with beautiful and large specimens oiN^atka 

 Stitderi and other fossils ; (4) the Venus bed became 

 lighter in colour and contained flint pebbles, but it 

 contained the same fossils, though not in quite the 

 same proportion as elsewhere ; (5) underneath the 



