EMBRYOLOGY 389 



forceps and pieces of the walls torn away, and the eggs pushed out 

 of the compartments formed by their choria and hardened as 

 desired. Good results are also obtained by heating to 80° C. for 

 ten minutes in liquid of Kleinenberg, and preserving in 70 per 

 cent, alcohol. This causes the envelopes to dilate and stand off 

 from the surface of the egg, so that they can easily be dissected 

 away. 



Heymons {Zeit. wiss. ZooL, liii, 1892, p. 434), for young embryos, 

 incises the cocoon at the end by which it adheres in the body of 

 the mother, brings it for two minutes into water heated to 90° C, 

 and opens in Flemming, in which the embryo is dissected out. 



Morgan {Amer. Natural., xxii, 1888, p. 357) puts ova of Peri- 

 planeta for thirty minutes or an hour into eau de Javelle diluted 

 with 4 to 8 volumes of water and slightly warmed, which softens 

 the capsules. 



853. Coleoptera. Hirschler {Zeit. wiss. ZooL, xcii, 1909, 

 p. 628) fixes ova of Donacia (after incising the chorion) for two 

 to three hours in equal parts of sublimate of 6 per cent, and 

 nitric acid of 3 per cent. 



Gatenby {Qiia)-t. Journ. Mic. Sci., 1917) for Donacia uses 

 Petrunkewitsch or picro-nitric. In the latter case the chorion 

 must be incised. 



Saling (Dissert. Marburg, 1906, p. 10) fixes ova of Tenebrio 

 for about two minutes in a hot mixture of 40 parts of alcohol 

 of 96 per .cent., 4 of nitric acid, and 50 of saturated aqueous 

 sublimate ; or for three minutes in a hot mixture of 1 part of 

 formol with 3 of water. 



Karawaiew {Biol. Centralb., xix, 1899, p. 124) kills larvae of 

 Anobium in hot water, freezes them with ether spray, cuts away 

 a lateral strip, lets them thaw, and puts for twenty-four hours 

 into picro-sulphviric acid. 



854. Phalangida. The ova of Phalangium opilio possess a 

 chorion covered with yellow corpuscles that render them opaque. 

 Balbiani puts them into water with a few drops of caustic potash, 

 and raises to boiling-point. The ova are then laid on filter-paper, 

 and the chorion removed by rubbing with a camel's hair brush, 

 the vitelline membrane remaining intact, so that the embryo can 

 be studied through it. 



Henking's method {Zeit. wiss. ZooL, xlv, 1886, p. 86). Fix 

 with boiling water or Flemming. Preserve the ova in 90 per 

 cent, alcohol. To open the chorion, bring them back into 70 

 per cent, alcohol, which causes them to swell up so that the 

 chorion can easily be pierced with needles, and the ovum turned 

 out. 



855. Araneida. Kishinouye {Journ. Coll. Sci. Imp. Vniv. 

 Japan, iv, 1891, p. 55 ; Zeit. wiss. Mik., ix, 1892, p. 215) fixes 

 in water warmed to 70° or 80° C, puts into 70 per cent, alcohol, 



