oOC) CHAl'TEli XXV. 



Meere, iii, Heligoland, lyOO, pp. ^05 and 'Jlo) prefer formol with 39 vols, 

 of sea- water. 



Tnnicata. 



616. Ova.— Davidoff {Mitfh. Zool. 8taf. Nmpel, ix, 1, 1889, 

 p. nS) fixes the ova of Dlxlaplia witli a uiixturo of 3 parts 

 of saturated solution of corrosive sublimate and 1 of glacial 

 acetic acid for from lialf an liour to an hour ; or with a 

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

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

 cent, alcohol. 



Castle [Bull. Mas. Harvard Coll., xxvii, 1896, p. 213j 

 advises for ova of Ciona liquid of Perenyi for twenty 

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

 hours, and for the larvas picro-nitric acid. 



617. Test-Cells of Aseidians (Mokgan, Journ. of Morphol.,vi,\^Q(>, 

 p. 196). — 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. 8c. Nat., xix, 1893, p. 5) studies 

 the gemmation of the composite Aseidians either on entire 

 corms, which he first bleaches with peroxide of hydrogen and 

 then stains ; or by making sections, after auassthetising 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 jjer cent, 

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



RiTTEB {Journ. of MorpJi., xii, 1896, p. 150) recommends 

 for fixing Ferophora and Goodnivia picro-sulphuric acid. 



Brjjoxoa. 



619. Statoblasts. — Beaem {Bihl. Zool., Chun and Leucl-art, 

 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. 



