44 ON THE AGAMIC REPRODUCTION AND MORPHOLOGY OF APHIS 
to discover any aperture. Internally, however, the corresponding 
surface of the chorion appears as it were rough and uneven; and 
when caustic potass is added, it, like the rest of the inner surface of 
the chorion, exhibits a very curious marking, as if so many circles or 
more irregular figures were impressed upon it. The thickness of the 
papilla is about gggoth of an inch; and in young ova a delicate 
filiform appendage more than once appeared to be continuous with 
it: this, however, was invariably absent in fully-formed ova. 
At the opposite pole (fig. 4, A), the ovum presents a curious 
appendage, about ;3,5th of an inch in length, When the ovum is 
in its natural position within the ovary, the epithelium of the latter, 
which closes over it below, leaves a sort of chamber in which this 
appendage, ordinarily more or less closely applied against the chorion, 
is received. 
When the ovum is extracted, the appendage appears like a rope 
with loosened strands, or a closely-plaited membrane, and is seen to 
be coated with a clear gelatinous substance, in which many minute 
rod-like filaments of about 55th of an inch in length are imbedded. 
Treated with caustic potass, this clear substance and its imbedded 
particles are dissipated, and the central cord becomes less distinct ; 
but I have never yet seen it dissolved, and sometimes it seems alto- 
gether to resist the reagent. The rounded tubercle of the chorion to 
which it is attached, however, now clearly exhibits a central funnel- 
shaped body, continuous with the axis of the appendage, and appear- 
ing like a canal (fig. 4, C). 
Is this a micropyle, and what is the nature of the appendage? 
I regret that I have not the leisure to pursue the inquiry far enough 
to answer this question satisfactorily ; but I incline to think that the 
micropyle is really situated here. 
The albuminous papilla surrounding the bundle of spermatozoa in 
the impregnated ova of J/usca, Devia, and A/elophagus (Leuckart, /. ¢. 
1 After describing the cup-like micropyle at the anterior pole of the ovum of the Louse, 
Leuckart (2. c.) goes on to say—‘‘ Besides this micropylar apparatus at the anterior pole, 
there is at the posterior pole of the ovum a structure which attracts attention. It may be 
described as a blunt cone, which is attached rather on one side of the centre of the posterior 
pole, and has acquired a peculiar striated appearance by reason of its longitudinal folds, and 
band-like thickenings. The interior diameter of this structure measures 3!) ; the upper is 
less, about 35’; and the length is about the same. A hollow space is contained within this 
body, so that it might be compared to a bell; but it seems as if from the roof, or cupola, 
as it might be termed, of this bell, a number of closely appressed elevations and points 
depended. With respect to the import of this remarkable apparatus, I will only throw out 
the supposition that it is an apparatus of attachment. For a long time I thought I had dis 
covered in it a second micropylar apparatus ; but I renounced this view when I was unable 
to discover any aperture in it.” (p. 140.) 
