HARDWICKE'S SCIENCE-GOSSIP. 



277 



labour requisite for the production of a greater number 

 of specimens cannot be secured. The laboratory will 

 include an educational, and an exchange and mart 

 department. For further information, we refer our 

 readers to 7, Machell Road, Nunhead, London, S.E. 



ZOOLOGY. 



Setting Board for Lepidoptera, &c. — The 

 setting boards used by most entomologists possess 

 this disadvantage — that they cannot be used for 

 setting insects in the Continental fashion, and in 

 some cases the butterflies must be set at the very 

 bottom of the pin, as the wood at the bottom forms 

 an impassable barrier to pins. The enclosed sketch 

 shows a setting board in which these difficulties are 

 obviated. The grooved cork, a, instead of being 



like that adopted by himself, viz. a pond excavated 

 to the depth of three and a half feet, near the sea, 

 and connected with the latter by a trench two feet 

 wide, and three and a half deep ; a wooden dia- 

 phragm in a shape of a perforated box, lined with 

 cloth, and filled with clean sand, so that no matter 

 could get to the pond without first filtering through. 

 This was adopted in order to exclude natural fry 

 from the pond. Mr. Ryder shows that food for the 

 oyster spat is rapidly generated in such an enclosure. 

 The density of the water is not materially affected by 

 the rain, and, moreover, ponds may be readily ex- 

 cavated in salt marshes, and can probably be used 

 for fattening oysters for market. In getting the 

 oyster spawn, the right shell of the adult mollusc 

 was removed, and the reproductive organs were 

 stroked with a pipette to force out the eggs and milt. 

 These were mixed together in water, and allowed to 

 stand in pails for a few hours, until the ova had 



Fig. 180. — Setting Board for Lepidoptera. 



glued to one wooden board, is fastened on to the two 

 boards, B B, the groove between them corresponding 

 exactly with the groove in the cork. These in turn 

 are held together by three slips of wood, c c c, to 

 which they are firmly nailed. In setting insects the 

 pin should not be run into the groove just above the 

 slips, c c c. If run into the cork anywhere else, the 

 pin can be pushed through to any depth required, and 

 as a rule the slips, ccc, are so high that when the 

 board is laid down on a table none of the pins touch 

 the table. After setting the insects I cover the wings 

 by pinning down paper, and hang the setting board on 

 the wall in a dry room. — G. H. Bryan. 



Artificial Fertilisation of Oyster Spat. — 

 Mr. J. A. Ryder, the well-known American naturalist, 

 whose telegram to the effect that he had discovered a 

 method for artificially fertilising oysters we have 

 already recorded, gives a full description of his 

 method in the American weekly journal "Science," 

 for October 5th. He there concludes by stating that 

 oyster spat may be reared from artificially fertilised 

 eggs ; that such will grow just as fast in enclosures, 



passed on to the swimming stage. The spawn was 

 then distributed in various parts of the pond, and left 

 to take care of itself. Mr. Ryder says that pond 

 culture has the decided advantage of effectually ex- 

 cluding the great enemies of the oyster, whelks and 

 star fish. 



Infusoria as "Messmates." — At the recent 

 annual meeting of the American Society of Micro- 

 scopists, Mr. Kellicott gave an account of some 

 stalked Infusoria, one of which was new to science, 

 and had been named Cothnrnia variabilis, which were 

 found only in the gill chambers of the crayfish. They 

 were so abundant as to encumber the gills of their 

 host 



" Parrots in Captitity." — By W. T. Greene, 

 M.D., &c. (London : George Bell & Sons.) Part iv. 

 of this work is to hand, treating on the Alexandrine 

 parrakeet (Psittacus etipatriits). The ring-necked or 

 Bengal parrakeet (Psittacus tarquatus), and the 

 blossom-headed parrakeet {Psittacus cyanocephalus) 

 All are beautifully illustrated by coloured plates. 



