288 EMBRYOLOGICAL METHODS. 



633. Limulus. KINGSLEY (Journ. Morph., vii, 1892, p. 38) kills 

 ova by heating in sea-water to 70 or 75 C. and brings into alcohol 

 of 30 to 70 per cent. Similarly KISHINOUYE, Journ. Coll. Sci. 

 Japan, v, 1893, p. 56. 



634. Decapoda. REICHENBACH (Abh. Senckenberg Ges. Frank- 

 furt, xiv, 1886, p. 2) fixes ova of Astacus in water gradually warmed 

 to 60 or 70 C. (if the chorion should burst, that is no evil), hardens 

 for twenty-four hours in 1 to 2 per cent, bichromate of potash or 

 0-5 per cent, chromic acid, washes out for the same time in running 

 water, and brings into alcohol. Remove the chorion, and remove 

 the embryo from the yolk with a sharp knife. 



HERRICK (Bull. U.S. Fish, Comm., xv, 1896, p. 226) kills the ova 

 in hot water, shells and fixes in picro-sulphuric acid. 



For Homarus, see WAITE, Bull. Mus. Comp. ZooL, xxxv, 1899, 

 p. 155. 



635. Amphipoda. BELLA VALLE (Fauna u. Flora Golf. Neapel 

 xx, Monog., 1893, p. 170) puts ova of Orchestia by means of a pipette 

 into boiling, cold-saturated sublimate solution, removes them 

 instantly into sea-water, and thence into weak alcohol. If the 

 chorion does not burst of itself it must be pricked with a needle. 



636. Cladocera. HAEKER (Zellen. u. Befruchtungslehre, 1899, 

 p. 60) fixes females of Sida with winter eggs in a hot mixture of 

 100 c.c. alcohol of 70 per cent, with 1 to 2 c.c. saturated sol. of 

 sublimate. See also SAMTER, Zeit. wiss. ZooL, Ixviii, 1900, p. 176. 



637. Copepoda. KRUEGER (Arch. Zellforsch., vi, 1911, p. 173) 

 fixes ovaries of Harpactida in Zenker's mixture with 10 per cent, 

 of formol added. No other liquids give good results. 



Vermes. 



638. Rotatoria. JENNINGS (Bull. Mus. Harvard Coll., xxx, 1896, 

 p. 101) finds the best fixative for pregnant females is the strong 

 liquid of Flemming, but the ova must then be bleached with chlorate 

 of potash ( 575). 



LENSSEN (La Cellule, xiv, 1898, p. 428) fixes ova of Hydatina with 

 sublimate for twenty seconds. 



639. Turbellaria. GARDINER (Journ. of Morph., xi, 1895, p. 158) 

 finds the best fixative for ova of Polychoerus is a mixture of equal 

 parts of absolute alcohol and glacial acetic acid. 



BRESSLAU (Zeit. wiss. ZooL, Ixxvi, 1904, p. 219) fixes Mesosto- 



