. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. or less of a minutely tuberculated structure on its external surface. The ovum becomes of a regular short oval or nearly spherical form. If fecundation shall have occurred, the embryonic vesicle or cell makes its ap- pearance, and the phenomena of segmentation follow in rapid succession. Fig. 88*.. OVUM. [123] In others of the Nematoid Worms and more especially in Strongylus and the Gordiacei, it would appear from the researches of Meiss- ner, that the first germs of ova which take origin in the uppermost part of the ova
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. or less of a minutely tuberculated structure on its external surface. The ovum becomes of a regular short oval or nearly spherical form. If fecundation shall have occurred, the embryonic vesicle or cell makes its ap- pearance, and the phenomena of segmentation follow in rapid succession. Fig. 88*.. OVUM. [123] In others of the Nematoid Worms and more especially in Strongylus and the Gordiacei, it would appear from the researches of Meiss- ner, that the first germs of ova which take origin in the uppermost part of the ovarian tube multiply by an endogenous production, and that in this manner groups or bunches of the primitive ova are produced which are con- nected together by pedicles arising from the Fig. 89*. Formation and fecundation of the ova of Nematoid Worms. {According to Meissner.) a. A portion of the ovarian axis and early ova attached to it from the ovarian tube of Strongylus armatus. The axis column occupies the centre of the tube, and the ova are suspended to it by pedicles, supposed by Meissner to form micropyle apertures when they are detached. b. View given by Meissner of a set of the nearly ripe ova of Ascaris mystax, which he conceives are thus connected by pedicles to a central axis. c. Two mature ova of the same surrounded and in part penetrated by spermatic corpuscles. At the narrow angles of these ova a spermatozoon is seen passing into the interior by what Meissner has regarded as a micropyle formed by the detached pedicle. In the ovum to the right a spermatic cor- puscle is seen in the vitelline substance. The existence of such a micropyle aperture and pedicu- lated attachment of the ova in the Ascarides 1 re- gard as doubtful. <7. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Todd, Robert Bentl
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