SCIENCE-GOSSIP. 



341 



MoLLUscA OF Kent. — As I am engaged in com- 

 piling a list of the Land and Freshwater Mollusca 

 of Kent, I would ask any of the numerous readers 

 of Science-Gossip to furnish me with the records 

 of any of the rarer shells they may have found in 

 the "Garden of England." Records are par- 

 ticularly wanted of Vertigo (all species), Amalia 

 gagates. Avion subfuscus, Hyalinia draparnaldi, Helix 

 fusca, BuUmimis montanus, Pupa secale, Acicula lineata, 

 Dreisscnsid polymorpha, Spharium ovalis, Viviparus con- 

 tectus, and Planorbis glaber. — A. S. Kemiard, Benenden, 

 Mackenzie Road, Beckenham, Kent. 



Abnormal Oranges. — The oranges to which 

 your correspondents refer (ante page 307) are well- 

 known and greatly esteemed in the United States, 

 though until recently they have been but little 

 used in Britain. They are a perfectly distinct fruit, 

 properly known as the " Washington Navel." 

 They are almost invariably seedless. These oranges 

 are on sale in Britain, and are sometimes described 

 as " Washington Naval " or simply as " Naval 

 oranges." Of course, the incorrectness of this 

 name is obvious when one realises that the 

 derivation of the name " navel " is from the 

 peculiarity noted by your correspondents. — H. 

 Snoivden Ward, Farringdon Avenue, London, E.C.; 

 April 6th, 1897. 



Great Auk's Egg. — Mr. Stevens sold at his 

 Auction Rooms in King Street, Covent Garden, on 

 April 14th, another egg of the extinct great auk. 

 It originally came out of the collection of Mr. 

 Potts of Croydon, who had three specimens. Two 

 of these were sold about 1853 in the same room as 

 that on April 14th. One realised £2^ and the 

 other £^0. The third was retained for many years 

 afterwards by Mr. Potts, but eventually was 

 acquired by Mr. Leopold Field, the well-known 

 ornithologist. When the latter gentleman gave up 

 his collection, this egg and the skin of a great auk 

 were purchased by Mr. Rowland Ward of 

 Piccadilly, who sold the skin to the Hon. Walter 

 Rothschild for the Tring Museum, where we 

 believe there are now two skins. The egg was sent 

 to Mr. Stevens for sale in April, and reached the 

 sum of two hundred and eighty guineas. It was 

 purchased by Mr. Middlebrook, an enterprising 

 public-house proprietor of Mornington Road, 

 Regent's Park, London, who has attached to his 

 premises a small show to attract customers. In 

 this "free museum" is another great auk's egg 

 which Mr. Middlebrook also purchased at the 

 Stevens' Sale Rooms, some little time ago, for one 

 hundred and si.\ty-five guineas. The specimen last 

 sold by Mr. Stevens was well marked and in perfect 

 order. It is the third which has recently been 

 purchased in the same rooms, not for science's 

 sake, but for " bold advertisement." It is not for 

 us to complain how and when a purchase is made 

 in a public auction room, but we cannot help 

 feeling regret that one of these rare eggs has not 

 gone to the national collection at South Kensington, 

 where a good specimen is sadly needed. 



Rearing Dragon-flies. — Mr. James G. 

 Needham, of Ithaca. New York, who is engaged 

 upon a popular monograph of North American 

 dragon-flies, contributes to the April number of 

 the " Canadian Entomologist " a paper on rearing 

 these handsome insects. Ha^ ing described how 

 easy it is to collect the nymphs with the aid of a 

 garden-rake to pull out the water-weeds to 

 which the nymphs cling, or a water-net, Mr. 

 Needham proceeds to say : " They are quite easily 

 reared. I have found common wooden kits and 

 pails half filled with water, with screen or netting 

 covers, entirely satisfactory. A number of nymphs, 

 if near one size, may be safely kept together, 

 excepting a few notoriously cannibalistic ..^ischnina, 

 and if not grown may be fed upon such small 

 insects as a net will gather in any pond. A good 

 square meal once a week will keep them thriving 

 The water should be reasonably clean. Three 

 things must be observed : (i) there must be a 

 surface up which they can climb to transform; if 

 the sides of the kit are too smooth put in some 

 sticks ; (2) there must be room enough between 

 the netting cover and the water for complete 

 expansion of their wings ; (3) they must remain 

 out of doors where sunshine will reach them. 

 This last point is essential to success. There is 

 still an easier way to do it, and one which, when a 

 species is very common, will prove entirely 

 satisfactory. ... If one will go to the edge of the 

 water it frequents at the time of its emergence, one 

 may find nymphs crawling from the water, others 

 transforming, imagoes drying their wings and 

 others ready to fly, and thus may obtain in a few 

 minutes the material necessary for determining 

 nymphs and imago. The time of emergence may 

 be determined by noticing at what time pale young 

 imagoes are seen taking their first flight, and then 

 going out a little earlier. The unfortunate thing 

 about it is that many of the larger species transform 

 very early in the morning, and to take such 

 advantage of them one must be on the ground 

 between daybreak and sunrise. Imagoes should 

 be kept alive until they have assumed their 

 natural colours. It is most important that each 

 imago and its cast skin should be kept together. 

 Eggs, also, are easily obtained. If the ovipositing 

 female be captured, held by the fore- wings, leaving 

 the hind-wings free, and dipped by hand on the 

 surface of clean water in a vial or tumbler, an 

 abundance of eggs will usually be liberated.'' 



Some National Zoological Gardens. — An 

 interesting and comparative article upon the 

 National Zoological Park at Washintgon, U.S.A., 

 appears in the last Report of the Smith- 

 sonian Institution, under whose control it has 

 been placed. The total acreage occupied by the 

 Washington Zoological Gardens reaches about 

 167 acres, with ample supply of water for lakes, 

 ponds and inclosures. It was acquired by national 

 purchase about iSSg, since which it has been laid 

 out as a place for recreation of the citizens, as well 

 as for their instruction. With regard to size, we 

 understand, as becomes a national American in- 

 stitution, it is the greatest in the world, the 

 comparison being, in acres, W'ashington, 167 ; 

 London, 36; Paris, 17; Berlin, 60. With regard 

 to the population of animals on exhibition, 

 we believe London more than doubles that of 

 any other. For picturesqueness Washington will 

 doubtless take the palm, and its extent and 

 airiness should contribute to the healthiness of 

 the animals confined there. 



