SCIENCE-GOSSIP. 



a butterfly that I thought was an Aran-brown. 

 Among the land mollusca the common garden- 

 snail (Helix aspersa) was plentiful in a cultivated 

 garden. Nothing else turned up, but on the 

 Island of Aran, my son found on the walls of the 

 old ruins of Ihe Firbolg Fort, a singular dark 

 variety of Helix ericetorum. The animal was so 

 mottled with black, and apparent through the shell, 

 that when I first saw it I fancied we had found a 

 wandering colony of the European Helix terveri. I 

 hunted in vain for any fresh-water molluscs, such 

 as Bythinia or Planorbis. 



Of the flora, I regret to add I can say little, as I 

 am ignorant of botany, but I recognised Asplenhtm 

 trichomanes in great profusion and beauty, in the 

 old walls between Galway and Oughterard, as we 

 drove along ; and I found, after a search, the sun- 

 dew (Drosera) on some of the bogs. 



Mr. Scharffs paper will cause us to take a 

 greater interest in the subject and make closer 

 observations, if we visit Ireland again this ensuing 

 summer, which we hope to do. Certainly our 

 weather was inauspicious, cold north and north- 

 east winds the whole time, and yet I never saw 

 finer and larger fuchsias, really high bushes. 

 " Otterbourne," Budleigh, Salterton ; February, 1895. 



CADDIS-WORMS & DUCKWEED. 



TV TY attention was attracted last May by the 

 *■*■*■ remarkable manner in which some caddis- 

 worms cleared one of my vessels of duckweed 

 (Lemna minor and thin fronds of L. gibba). Five of 

 these creatures disposed of, on the average, 

 twenty plants daily, and I estimated that in a pond 

 covered with duckweed one caddis-worm to every 

 four square inches of the surface would not merely 

 check the growth but in the course of two months 

 would clear the surface of the duckweed altogether. 

 Though most of the plants are eaten, many die 

 from being partially devoured; and, as in this 

 species the larvae construct their cases of the 

 fronds, quantities of the plants are expended in 

 the constant repairs of their homes. Here, then, 

 is one explanation of the absence of duckweed in 

 certain ponds where caddis-worms abound, as in 

 the Black Pond at Oxshott. It is in the spring, 

 when the duckweed is beginning to cover a pond, 

 that these larvae are best able to carry out their 

 destructive mission . Perhaps some of the numerous 

 readers of this journal would be able to put these 

 results to the test of further observation. We 

 know far more of the forms of the Lemna: than we 

 do of the conditions in which they live, and an 

 agency that allows these plants to flourish in one 

 pond and banishes them from another may prove 

 to affect the distribution of these plants in different 

 regions of the globe. Hy. B. Guppy, M.B. 



6, Fairfield West, Kingston-on-Thames ; Feb. tfh, 1895. 



PERTHSHIRE SOCIETY OF 



NATURAL SCIENCE. 



By ,T. M. McGregor. 



*HPHE Perthshire Society of Natural Science was 

 founded in Perth on February 28th, 1867, 

 for the avowed purpose of " carrying on the 

 practical study of natural science, by the exhibi- 

 tion and preservation of specimens, the reading of 

 communications, by lectures, excursions, and by 

 the formation of a library and museum " ; and was 

 inaugurated on March 7th of the same year, under 

 the presidency of the late Dr. F. Buchanan-White. 

 The ordinary meetings of the Society were held in 

 the Glovers' Hall, George Street, until October, 

 1869. In this place the Society had no room for 

 the storage of specimens, so it was decided to look 

 out for more commodious premises, the members 

 being of opinion that " had the Society a room of 

 sufficient size in which to begin its museum, there 

 would be no lack of donations." It was not, 

 however, till October, 1869, that it was announced 

 that a room had been secured, at Kirkside, to serve 

 as a " store-room ' for the Society's collections. 

 In the Third Annual Report the members were 

 asked to assist " in getting up a complete museum 

 of the natural products of the county —now that 

 there is accommodation for them." These premises 

 were also found to be unsuitable for the purposes 

 for which they had been secured, so in May, 1870, 

 the Society moved to rooms in St. Ann's Lane, 

 which it continued to occupy till May, 1881. 



In the Eighth Annual Report we find the curator 

 (Col. Drummond-Hay) complaining of want of 

 space, but the Society seems to have remained in 

 an apathetic state until November 15th, 1875, when 

 the Council took into consideration " the propriety 

 of having larger rooms that might be fitted up as 

 a museum." It was ultimately agreed to take a 

 lease of a room in the Exchange Buildings, George 

 Street, which seemed suitable. Before this was 

 done, however, further consideration of the matter 

 had led to broader views. At the Tenth Annual 

 Meeting, in 1876, Sir Thomas Moncreiffe reviewed 

 the whole matter of the Society's museum, pointing 

 out the difficulties that lay in the way of depositing 

 valuable specimens in the rooms then occupied by 

 the Society, and mentioned a site which might be 

 secured for a suitable museum. 



No definite steps were taken in this direction 

 until March, 1877, when Sir Thomas Moncreiffe 

 (then President of the Society), in his presidential 

 address, again brought forward the scheme of 

 building a natural history museum (in South Tay 

 Street), together with a large public hall. The 

 proximity of this large public hall to the museum 

 would make the former available for lectures, 

 conversaziones, etc., for which the lecture-room in 

 connection with the museum might prove too 



