78 Observations upon the Habits, Structure and | February, 
in a separate membrane or cell, any one of which may open and 
discharge its contents without affecting the rest of the case. 
Under the microscope these cases appear like small bags of mar- 
bles or bunches of grapes, except that most. of the ova show a 
lighter, roundish spot near the center, which represents a nucleus, 
the nucleolus not being visible (Fig. 4, Pl. 11) After escaping 
from the cases and becoming free in the branchium, the ova in all 
probability, pass out of the body, by way of the branchiopore, in 
the water which is being constantly expelled from this orifice 
during the process of feeding. Up to 1873 this was considered, by 
careful observers to be the only method by which the ova could 
possibly escape into the surrounding medium, and Quatrefages says 
that he saw them, under the microscope, pass from this aperture. 
But Kowalevsky, in his paper upon the development of Amphi- 
oxus,' says that Ae saw the eggs issue from the mouth of the 
. female in bunches of fifteen or twenty, and hence concludes that 
they are normally extruded from this opening. This abnormal 
proceeding on the part of Amphioxus has been questioned by 
Wm. Müller? on the grounds that the branchial slits are too narrow 
to admit of the passage of the ova in this direction, and Prof. 
Huxley seems to be of the opinion? that if this proceeding took 
place as described by Kowalevsky, that it was accidental, and due 
to some of the ova in passing out by the branchiopore getting 
caught in the openings of the lateral folds, being carried along 
the hollows of these folds and discharged at their anterior open- 
ings into the mouth cavity and thence out of the body. But this 
would not account for their issuing in bunches of fifteen or 
twenty, and moreover, as there are no such openings to the meta- 
pleura (ante p. 6), the ova could not have passed in this direc- 
tion. Prof. Ray Lankester‘ sides with Kowalevsky, and says that 
in all probability the ova do pass from the mouth, but if not by 
the branchial slits, then by certain openings which exist, one upon 
either side, and connect the branchium with the buccal cavity. 
This connection has not been noticed by previous observers, 
although Prof. Lankester thinks that these’ openings are the ones 
1 Entwicklungsgeschichte des Amphioxus lanceolatus. Von Dr. A. Kowalevsky, 
Mem. de |’Acad. Imp. des Sciences de St. Pet tersbourg, vime série. Tome x1, No, 
4, p- 1. St. Petersburg, 1867. oo 
2 Ueber das Urogenital system des Amphioxus, &c. Jenaische Zeitschrift, Vol. Xe 
p. 94. 1875. z 
=- 3Classification of the Animal Kingdom. PELE Hosjeg. Quar. Jour. 
Microscop. Sci., Vol. 15, p- 54. 1875. 
* Loc. tit., p: 
