H. J. Clark on Actinophrys Eichornii. 331 
Art. XXXil.—On the cellular structure of Actinophrys Hichornii ; 
by Professor H. JAMES CLARK.* 
Schrift fiir wissenschaftliche Zodlogie, and showed that, even suppo- 
___ Sing Kolliker to be correct, the division of the mass of the body 
into an exterior and an interior portion, the former containing 
much larger vacuoles than the latter, indicated a heteromorphous 
. organization, and tended toward specialization of parts. He also 
_ added that he could not agree with Kolliker, that Actinophrys 
is a homomorphous mass with vacuoles, but that he was convin- 
ced that the so-called vacuoles of the outer and inner layers are 
true cells, with a distinct wall about them; a wall that could be 
easily recognized with the help of the better sort of microscope- 
Objectives of the present day. Owing to the exceeding transpa- 
rency of the organism, no ordinary objective will show the walls; 
but, with a one-quarter inch lens, of one hundred and fifty de- 
grees angular aperture, made for him last June, by Tolles, of Can- 
astota, N. Y., he had no difficulty in working, with the proper 
adjustment and corrections, through a sufficient depth of water 
| _ to completely cover the Actinophrys (A. Eichornii), and could 
| ___ Teadily detect the walls, not only of the superficial cells, but also 
} ‘Of the innermost ones.’ 
What is remarkable, too, the pseudopodia, as frequent and 
7 . 
careful observations have led him to determine, invariably alter- 
* From the Proceedings Boston Soc. Nat. Hist., 1863, p. 281. 
* The unprecedented working distance, which accompanies the great angle of aper- 
i enti eak more fully of its excellence. 
is the s, prompts me to 
Ithas been the chief desideratum of naturalists to obtain a large increase in 
ing di i 
stance, and consequently great inconvenience in t 
are not correspondingly thin. The idea animals it 
Native element, with such lenses, could never be indulged in, for fear of ruining the 
inch thick, and with some room to spare above that. The wor! 
“rough water I have not measured fe et but that can be inferred ae the 
‘difference between its refraction and that of glass, The defining power of this lens 
Bs certainly unsurpassed, if not unequalled.—x. J. c- 
