316 GASTEROPODES. 
spawning, though considerably exhausted, it produced four volutes at 
the surface of the water, while swimming supine ; and twelve days later 
still, two volutes additional. The extenuation concomitant on the 
breeding of these animals is very remarkable. The specimen (Plate XLV. 
figs. 25, 26) is evidently much reduced from that cause. If surviving so 
important an incident, prolific animals probably resort to the depths of 
the sea. 
The diameter of the mass of spawn is commonly from an inch to about 
an inch anda half. But here there is no uniform rule. A very fine, curious, 
and interesting example of spawn, is represented in Plate XLV. fig. 27. 
But the form here is very complex whereas it is usually simple, consist- 
ing of a curve nearly plain, or indented throughout. The present spawn 
occupied a stone on the shore: it consisted of two complete volutes ; but 
instead of these forming a single gelatinous thread or rope full of ova, 
here was a gelatinous rope, four lines in diameter, encircled by such a 
gelatinous thread in 120 circles, occupying the whole two volutes, from 
the centre to the extremity. I feel much perplexed how to describe this 
product intelligibly. But we may suppose the whole extended in a straight 
line, instead of preserving its curve, and in that case forming a cylinder, 
with a thread wrapped spirally around it. I doubt not that some illusion 
doubled the number of encircling spirals, as the same thread might 
appear next the eye, and as another beyond it. But such was the 
appearance, whatever might be the reality. 
The spawn of this Eolis, I have said, resembles grains of rice. In 
the encircling spiral of the specimen before me, were found five or more 
such grains (fig. 12), somewhat enlarged. Under the microscope the 
grains consisted of a cluster of broad ovoidal transparent ova, each occu- 
pied by four or five Nautilines, the greatest number seen in any of them. 
At that time I had not previously observed more than a single Nautiline 
in the ovum. Here it was otherwise ; nor did any illusion mislead the 
eye, for the Nautilines were very active, continually interchanging 
places, crushing through their fellows in their respective prisons, as if 
compressed for want of room. The cilia of what were supposed their 
cylinders had at that stage become quite corispicuous. On June 16th, 
