:>06 CHAPTKK xxv. 



Meere,.iii, Heligoland, 1900, pp. 205 and 213) prefer formol with 39 vols. 

 of sea- water. 



Tunicata. 



616. Ova. DAVIDOFF (Mittli. Zool Stat. Nvapel, ix, 1, 1889, 

 p. 118) fixes the ova of Dislaplia with a mixture of 3 parts 

 of saturated solution of corrosive sublimate and 1 of glacial 

 acetic acid for from half an hour to an hour ; or with a 

 mixture of 3 parts of saturated solution of picric acid and 1 

 of glacial acetic acid for threo to four hours ; then 70 per 

 cent, alcohol. 



CASTLE (Bidl. Hum. Harvard Coll., xxvii, 1896, p. 213j 

 advises for ova of Ciona liquid of Perenyi for twenty 

 minutes, followed by 70 per cent, alcohol for twenty-four 

 hours, and for the larvae picro-nitric acid. 



617. Test-Cells of Ascidians (MORGAN, Journ. of Horpliol., iv, 1890, 

 p. 195). Tease fresh ovaries in very weak osmic acid, wash in distilled 

 water, treat for half an hour with 1 per cent, silver nitrate, wash for 

 half an hour in 2 per cent, acetic acid and reduce in sunlight. Imbed 

 in paraffin. By this process the limits of the follicle cells are demon- 

 strated. 



618. Buds. PIZON (Ann. Sc. Nat., xix, 1893, p. 5) studies 

 the gemmation of the composite Ascidians either on entire 

 conns, which he first bleaches with peroxide of hydrogen and 

 then stains; or by making sections, after auresthetising the 

 colonies with cocain of 1 : 1000, fixing in glacial acetic acid 

 or picro-sulphuric or liquid of Flemming, and staining in toto 

 with borax carmine or alum carmine, or with a strong 

 solution of methylen blue in alcohol of 90 or 100 per cent, 

 (after BERNARD, ibid., ix, 1890, p. 97). 



HITTER (Journ. of Horph., xii, 1896, p. 150) recommends 

 for fixing Perophora and Goodsiria picro-sulphuric acid. 



Bryozoa. 



619. Statoblasts. BRAEM (Bill. Zool., Chun and Leuckart, 

 6 Heft, 1890, p. 95) fixest statoblasts of Cristatella with hot 

 concentrated solution of sublimate for ten minutes, brings 

 them into water and there incises them with a razor, and 

 after half an hour passes them gradually into alcohol. He 

 stains with picro-carmine. 



