GASTEROPODES. 291 
The spawn of this animal is produced in the form of tape or ribband, 
about an inch broad, and above a line thick. The length depends on the 
dimensions and the age of the parent. One of middle size (for few attain 
the dimensions as above assigned) produced what must have contained at 
least 20,000 ova, in the course of ten days, ending with the first week 
of February. 
The orifice of the oviduct is on the right side. The end of the 
spawn first produced is affixed to a solid substance, and the remainder is 
delivered as a broad waving frill, apparently in one continuous web, 
where in a convenient position. But probably, from some inconvenience, 
that which is just referred to was discharged in interrupted portions, not 
above an inch long, and about three lines broad, resembling a thin white 
silk ribband. Here the ova were pure white, spherical, not the twentieth 
of a line in diameter, lodged amidst an albuminous mass. More than 
one is the thickness of the ribband. Under the microscope the ovum 
consists of a white central speck, within its own peculiar albumen.— 
Plate XLIII. fig. 5. 
Perhaps the spawn sometimes appears a belt or web, in spiral 
arrangement, such as Plate XLII. fig. 1. 
But here I must be allowed to express some embarrassment, espe- 
cially regarding the parentage of certain extraordinary quantities of 
spawn, sometimes occurring in the course of observation. The Doris, it 
is true, is a remarkably prolific creature, like some of the other mollus- 
cous animals ; and it does baffle conjecture to account for the fate of a 
vast proportion of its young. The contents of a single mass of spawn, 
certainly the produce of a single parent, seems to exceed computation. 
Two examples may be quoted. 
A mass occurred in February, which had been deposited on the out- 
side of the lower valve of an old oyster-shell, to which the upper valve 
was still united. This consisted of a waving belt or ribband, from seven 
to nine lines broad, a line thick, and which could not be under two feet 
in length, if extended. It was affixed by the edge, in such a position as 
to be erect, and resembled fine white frills—Plate XLIII. fig. 2. 
Herein were contained ova in millions. 
