Volume 2

Researches in embryology. Ser. 1-2. / [M. Barry].

  • Barry, M. (Martin), 1802-1855
Date:
1839
Catalogue details

Licence: Public Domain Mark

Credit: Researches in embryology. Ser. 1-2. / [M. Barry]. Source: Wellcome Collection.

    51/100 (page 347)
    free from the dark granules or globules of the preceding stage. One of the central vesicles in this figure presented an indistinct spot. The object in fig. 81. is from the ovary of the common fowl. Its central part resembled the objects in figs, 83 and 84. from the Rabbit (par. 292. Note.). Facts noticed by preceding Observers, cited to show the Accordance in various respects between the Development of Mammalia and that of other Animals. 243. I have copied from CARUs-f- the drawing of a structure (Plate VIII. fig. 131.) occurring in the ovum of one of the Mollusca,— Unio tumida. With this I would com- pare fig. 130, The latter represents a structure of the same kind as that which in Mammalia closely invests the embryo, and seems to enter into the formation of the amnion; the former exhibits an object which, in. the molluscous animal above-men- tioned, appeared to Carus to be the foundation of the shell. The Professor saw a similar structure in ova of Anodonta. The “ rhombick fields” in the figure from Carus, as that author terms them, (which appear to me to have been vesicles with nuclei) seemed to become more numerous as development proceeded. With this ob- servation I would compare what has been stated (par. 174 to 178. 180. 314 to 318.) regarding the greater number and smaller size of the successive sets of vesicles in the mulberry-like structure met with in several stages of the mammiferous ovum, (Plate VI. figs. 105^ to 110., Plate VIII. fig. 130.). 244. In the ovum of some of the Crustacea, there occurs a striking resemblance in appearance to the structure, just referred to in the Mammalia, when it has attained a more advanced stage. Such for instance is the case in the ovum of the Crafish, Astacus JluviatiUs%. Spiders present in their ova a resemblance equally remarkable. With Plate VI, fig. 114. am. I would compare, for example, the ova of Epeira diadema, as figured by Herold§. Now in those animals, the structure which I suppose to cor- respond to that marked am. in my figures, appears to enter into the formation of the outer covering of the abdomen. 245. In none of the figiires of the authors last referred to, have I been able to dis- cover any trace of what seems to me entitled to be denominated a “germinal mem- brane.” But, on the other hand, there is to be recognised in a great number of those figures, an unquestionable similarity at the part where the embryo arises, to the cor- responding part in the ovum of Mammalia. 246. Rathke describes a depression in the ovum of the Crafish 1|, and also in that of Bopyrus squillarum^, which in some respects appears closely to resemble that which I suppose to be the corresponding part in Mammalia, as shown in Plate VI. fig. 114. a.p. t Neue Untersuchungen uber die Entwickelungsgeschichte unserer Flussmuschel, Tab. II. fig. 1. X Rathke, Flusskrebs, Tab. I. § Untersuchungen fiber die Bildungsgeschichte der Wirbellosen Thiere im Eie, Theil I. 11 Flusskrebs, Tab. I. fig. 2. ^ Zur Morphologic Reisebemerkungen aus Taurien, p. 44.