Nucleus of the Aninial and Vegetable " Cell.^^ 227 



thor increased in size, and the peripheral cytoblasts are dividing into minuter 

 cytoblasts, i. c, they have formed cells which exhibit (are being reproduced by) 

 a cell-formation in their interior. (Phil. Trans. 1841, Plate XXV., figs. 165- 

 167.) 



Fig. 38. From the same ovary. Portion of the membrane of an ovisac, which 

 was elliptical, and \'" in length as it lay crushed under glass. It still pre- 

 sented a pale tinge of red, as well as a trace of the minute cells of which the 

 membrane is composed. (Phil. Trans., 1841, Plate XXV., fig. 172.) 



Fig. 39. Blood-corpuscles, and cells &c. derived from blood-corpuscles, of the 

 Lobster, Tadpole, Cod, Chick in ovo, Rabbit, and ftctal Sheep and Ox. All drawn 

 on the same scale; magnified 600 diameters. (Phil. Trans., 1840 and 1841.) 

 Most of the larger of these bodies are very much in outline. 



Fig. 40. The germinal vesicle, and some of the surrounding substance, in an 

 ovum of the Tiger, after the ovary had been for a short time macei*ated. The 

 germinal vesicle had become elliptical, and out of the germinal spot there had 

 arisen three concentric cells. (Phil. Trans., 1839, Plate V., fig. 89). See the 

 description of fig. 41. 



Fig. 41. A nucleus in its cell. The nucleus consists of two concentric cyto- 

 blasts, the inner being the one last formed. The nucleus of this cell was the 

 rudimental embryo of the Rabbit. (Phil. Trans., 1839, Plate VIII., fig. 148.) 



Fig. 42. The nucleus of one of the twin cells in an ovum of the Rabbit of 17 

 hours, from the Fallopian tube. Its external part consisted almost entirely of 

 cytoblasts. (Phil. Trans., 1840, Plate XXIV., fig. 192.) 



Fig. 43. Nucleus of one of the transitory cells in an ovum of the Rabbit from 

 the Fallopian tube, of the same age as that in the preceding figure. (Phil. 

 Trans., 1840, Plate XXIV., fig. 189.) 



Fig. 44. After Harless. . a, /J, y, Cells of ganglion-globules in the lobus elec- 

 tricus of the Torpedo Galvanii ; shewing a connection between nef vous fila- 

 ments, and what Dr Harless terms the nucleus of an inner cell. See pp. 217, 

 218 of this Journal. 



Fig. 45. 06, An ovarian ovum of a rabbit killed in the state of heat; in diame- 

 ter iV'". c, Germinal vesicle. /3, The pellucid centre of the altered germinal spot 

 on a larger scale, from an ovum of the same ovary as the ovum a. (Phil. 

 Trans. 1840, Plate XXII., Fig. 162.) Compare with Fig. 46. 



Fig. 46. After H. D. S. Goodsir. Ovules of Caenurus cerebralis. a, " Fifth 

 stage of ovule. C, primary germinal vesicle ; D, primary circle of cells; E, 

 central cell of primary circle of cells become larger ; F, its nucleus, become 

 larger and nodulated." /J, " Ovule of Caenurus, very far advanced in the dis- 

 coidal period of developement. The concentric circlets of cells are seen ; and 

 the central circlet near to the lower edge as it was pressed between the plates 

 of glass, shewing that there is elevation, to a certain extent, during the latter 

 stages of this period. A, external covering of gemmule ; C, some of the con- 

 centric circles of young cells; C, central cell of last formed circlet; D, its nu- 

 cleus and clear space." (Trans. R. S. E., 1844, Vol. XV., Plate XVI., Figs. 5 

 and 9.) 



PLATE II. 

 Fig. 46^. Blood-corpuscles from the edge, poaterior surface, and neighbour- 



