462 CHAPTER XXXIV. 



the two inner ones, which have suffered less from the opera- 

 tions. 



See also 20. 



The methods recommended for Lamellibranchiata some- 

 times give good results with Gastropoda. 



S. Lo BIANCO advises that Prosobranchiata, arid, amongst 

 the Heteropoda, Atlantidae, be narcotised with 70 per cent, 

 alcohol, 16. Opisthobranchiata ought not to give much 

 trouble, and I recommend sudden killing with liquid of 

 Perenyi, or the acetic method, 824. Aplysia may first be 

 narcotised by subcutaneous injection of about 1 c.c. of a 5 

 to 10 per cent, solution of hydrochlorate of cocaine (EoBEKT, 

 Bull. Scient. de la France, etc., 1890, p. 449 ; Zeit.f. iviss. Mik., 

 ix, 2, 1892, p. 216), or (SCHONLEIN, Zeit. Biol., xxx, 1893, 

 p. 187) 1 c.c. of 4 per cent, solution of Pelletierin. For 

 Lo BIANCO' s various methods see the original, p. 467. 



For Pteropoda in general, liquid of Perenyi. Creseis is a 

 difficult form. S. Lo BIANCO advises the alcohol method, 

 16. For the Gymnosomata he narcotises with O'l per cent, 

 chloral hydrate. 



Note the hydroxylamin method of HOFEE, 20. 



For preservation it may be noted that for Heteropoda and Pteropoda. 

 formaldehyde (preceded by due fixation in a chromic or sublimate solution) 

 is an admirable medium, so far at least as macroscopic appearances are con- 

 cerned, and for this purpose superior to alcohol. 



For terrestrial Gastropods see the Asphyxiation method, 

 23. See for removal of mucus, MARCHI, Arch. mik. Anat., 

 1867, p. 204. 



828. Eyes of Gastropoda (FLEMMING, Arch. f. mik. Anat., 

 1870, p. 441). The difficulty here is to obtain the excision 

 of an exserted eye. It is impossible to sever the exserted 

 peduncle in a living animal without its retracting, at least 

 partially, before the cut is completed. Never mind that ; make 

 a rapid cut at the base, and throw the organ into very dilute 

 chromic acid, or 4 per cent, bichromate ; after a short time 

 it will evaginate, and remain as completely erect as if alive. 

 Harden in 1 per cent, osmic acid, in alcohol, or in bichromate. 



CARKIERE (Zool. Anz., 1886, p. 221) removes the eye, 



