SPERMATOGENESIS IN MYXINE GLUTINOSA. 185 
simplicity much greater than is found in the more highly 
organised Invertebrates. As a consequence of this simplicity 
the history of the testis approximates very closely to that of the 
ovary. In fact, we cannot help regarding the male follicle and 
the female follicle as exactly, or almost exactly, homologous. 
My sections of developing testes lead me to conclude that only 
a single germ-cell is usually included in a follicle. In the 
female follicle the germ-cell undergoes no multiplication after 
its isolation from the germinal tissue, while in the male follicle 
the included germ-cell multiplies by division, and each of the 
numerous spermatocytes produced gives rise to several sperma- 
tozoa. It seems to me probable that future researches upon 
the development of the testes in the higher Vertebrates, in the 
light of our knowledge of the testis of Myxine, will afford us a 
better comprehension than we yet have of the complicated 
structure of the former. 
W. Miller (1) has shown that the testis of Petromyzon is 
composed of follicles and cells similar to those of the testis of 
Myxine. Probably the development of the testis and the 
process of spermatogenesis are also similar, but these have not 
yet been investigated. 
List oF REFERENCES. 
1. W. Miiter.—Ueber das Urogenitalsystem des Amphioxus und der 
Cyclostomen, Jena Zeitschr., Bd. ix, 1875. 
2. J. T. Cunntnenam.—On the Reproductive Elements in Myxine 
glutinosa, Quart. Journ. Micr. Sci., vol. xxvii, 1886. 
3. Friptyor Nanszey.—A Protandric Hermaphrodite amongst the Verte- 
brates, Bergens Museums Aarsberetning for 1887. 
aS 
. JEnsEN.—Recherches sur le Spermatogénése, Arch. de Biol., iv, 1883. 
a 
. BLoMFIELD.—Spermatogenesis in Harthworms, Quart. Journ. Mier. Sci., 
xx, 1880. 
6. BLOMFIELD.—Spermatogenesis in Helix and Rana, Quart. Journ. Micr. 
Sci., xxi, 1881. 
