Miscellaneous. 395 
the proper adjustment and corrections, through a sufficient depth of 
water to completely cover the Actinophrys (A. Hichhornit), and could 
readily detect the walls, not only of the superficial cells, but also of 
the innermost ones *. 
What is remarkable, too, the pseudopodia, as frequent and careful 
observations have led him to determine, invariably alternate with the 
cells of the exterior layer; that is, they are prolongations of the in- 
tercellular amorphous substance of the body. This fact would seem 
to add to the proof that the so-called vacuoles are really cells; other- 
wise it would be hardly credible that simple vacuoles, which come 
and go in an amorphous substance, should always alternate with the 
pseudopodia. 
Sometimes a pseudopod moves very rapidly, especially when it has 
seized upon some victim ; for then it retracts with a sudden jerk, and 
draws the prey close to the body, which finally engulfs it in the same 
manner as does dmeba. The pseudopodia exhibit an adhesive power 
which is remarkable when we consider the size of the animals which 
are sometimes drawn in by them, and in this respect remind one of 
the ‘‘adhesive vesicles’’ in the anchors of Lucernaria, which hold fast 
to bodies with the greatest tenacity, and, to all appearances, by simple 
contact, just as glue and mucus adhere to anything which touches 
them. [See Prof. Clark’s paper “‘on Lucernaria, the Coenotype of 
Acalephee,”’ Proc. Bost. Soc. Nat. Hist. vol. ix. (1862) p. 52, and also 
reprinted, ‘‘ with additions and notes,” in the ‘ Annals of Natural His- 
tory,’ July 1863, p. 19.] In a Diffugia (very near D. proteiformis), 
Prof. Clark had observed that whenever the pseudopodia contract, 
they invariably become strongly wrinkled transversely ; and, as he 
could not detect the least trace of an envelope or wall-like layer on 
this part of the body, he believed that the wrinkling is peculiar to 
the substance of the pseudopodia. 
[In connexion with this, I will take the opportunity to assert that, 
* [The unprecedented working distance which accompanies the great 
angle of aperture in the above-mentioned lens prompts me to speak more 
fully of its excellence. It has been the chief desideratum of naturalists to 
obtain a large increase in the working distance of those lenses which have 
a great angle of aperture; but hitherto the latter condition has seemed to 
involve necessarily an excessively short working distance, and consequently 
great inconvenience in the investigation of all bodies which are not corre- 
spondingly thin. The idea of studymg marine animals in their native 
element with such lenses could never be mdulged in, for fear of ruiming 
the objectives by contact with salt water. At last we are relieved from this 
restraint ; for within the last four or five years a great improvement has 
been made in this respect by opticians, at least by Mr. Tolles. The most 
recently constructed lens whicli I have received from that gentleman was 
made last June; it is a one-quarter-inch objective, with an angular aper- 
ture of one hundred and fifty degrees, and a most unexpected working 
distance of one-fiftieth of an inch for uncovered bodies. By experiment, 
I also find that. it works through a glass covering fully one-fortieth of an 
inch thick, and with some room to spare above that. The working distance 
through water I have not measured accurately ; but that can be inferred 
from the difference between its refraction and that of glass. The defining 
power of this lens is certainly unsurpassed, if not unequalled.—H. J.C. ] 
