1884.] 63 [Hyatt. 



There are so many authors whose works ought to be con- 

 sidered, that the limits of this paper would be far exceeded, 

 if an attempt was made to quote from all of them. It is only- 

 essential to note the results of Yon la Valette St. George, who 

 more than any other has studied in all branches of the Animal 

 Kingdom, and a few other authors. St. George supports the con- 

 clusions of Kolliker (Op. Cit. and Henle Handb. d. Anat. d. 

 Mensch. Bd. ix, p. 356), in his first article in Arch. Micr. Anat. 

 vol. i, p. 407, 1865, saying that he holds, " die Korper oder Kopfe 

 der Samenelemente fur umgewandelte Kerne." In his fifth 

 communication he reiterates this statement, adding that he has 

 also verified Henle's discovery, that the tail is developed differ- 

 ently from the body out of the plasma of the cell and not from 

 the nucleus, (ibid, vol. 15, 1878, p. 263.) In the fourth communi- 

 cation (ibid, vol. xn), he, with reference to the Batrachia, gives the 

 description of the division of the Ursamenzelle, or spermatogonia, 

 the erection of a cellular cyst around it by coalescence of the 

 neighboring cells, forming the Samenfollikel, the division of the 

 nucleus into numerous nuclei, the formation of an outer per- 

 ipheral layer, and an inner portion, the outer being com- 

 posed of nuclei which are resorbed and with their own sur- 

 rounding plasma form the " Cystenhaut," which eventually 

 becomes transformed into Sperm atocy ten or cells, which in turn 

 give rise to Spermatozoa. The inner remaining nuclei together 

 with what remains of the original nucleus form the Cystenkern 

 which takes no part in this process. The author then, p. 820, 

 declares his belief, that though only stated with reference to this 

 one class this appears to embody a general law of development 

 for all animals. The conclusion on p. 821, that the spermato- 

 cyst is the homologue of the ovum has also great interest in con- 

 nection with other parts of this paper. The first discovery of 

 the cystenkern appears to have been due to Remak's work upon 

 the frog. (Mullers Archiv. 1854, p. 253.) Butschli (Morph. bedeut. 

 d. Richtungsblabchen, Zool. Anzeig. iv, no. 1, 1884), declares 

 himself in accord with Minot's views of the meaning and homol- 

 ogy of the Cystenkern of St. George, or the Spermblastophor of 

 Bloomfield with polar globules, but expresses some doubts with 

 regard the minor points of his comparisons. Semper's researches 

 upon the generation and development of spermatozoa were the 



