FOUND IN THE NORTHUMBERLAND LAKES. 409 
figs. 3 6, & 4 e, is completely exposed, and rests, as it were within 
the mouth of a shallow cup, figs. 3 e, e, & 4 g, the contracted enve- 
lope. The egg remains in this position for a day, and sometimes 
longer, attached to the body of the parent by a short, thin pedicle, 
figs. 3d & 4 f; the margins, at first, are generally undulated, as 
in fig 4 ; afterwards the egg becomes almost completely globular. 
It is ultimately detached, and soon fixes itself to some foreign 
body. On watching one individual through the microscope, the 
egg was observed to separate from the parent, and to move slowly 
away. No ciliary action could be detected to account for the 
motion ; but it assuredly passed out of the field of view as often 
as the instrument was adjusted: in another instance, however, no 
motion could be observed. The egg, Pl. VII. fig. 6, in the course 
of an hour or so, became stationary, and several minute globules, 
a, a, a, which had been noticed sticking to it from the first, Pl. 
VIII. fig. 3 ¢, c, enlarged, and others made their appearance: they 
soon assumed the character of delicate cells, Pl. VII. fig. 7, filled 
with globular bodies, with dark margins. These globules are 
probably composed of some tenacious mucus with which to glue 
the ege to any substance on which it may happen to settle. Soon 
after attachment, these bodies disappear, and the egg, which is 
now perfectly circular, is seen to be surrounded by a narrow, 
transparent rim, indicating the presence of a distinct chorion ; 
the under side of the egg being flattened, the upper side convex, 
opake, and rosy as at first. 
I have not been able to determine, with precision, how many 
eggs are produced by each polype, but certainly no great number, 
probably not more than three or four, and in some instances per- 
haps only one. On one occasion, after the egg separated from 
the animal, the latter gradually dwindled in size, and ultimately 
disappeared. Most frequently, however, the polype is not mate- 
rially altered on giving birth to an egg; and occasionally two, 
Pl. VIII. fig. 1 d, d, are in process of development at the same 
time, generally from opposite sides, one being more advanced than 
the other. 
The male organ is only developed at the time the eges make 
their appearance. In August, shortly after the polypes were pro- 
