310 GASTEROPODES. 
specimens remained, the one smaller and weaker than the other. The 
union of this pair seemed to have taken place, and to have been produc- 
tive. Yet soon afterwards, the larger unexpectedly devoured its mate, 
all except a portion, then conjectured to belong to the head, from which 
it endeavoured during hours to extract further nutriment. 
A third specimen, previously in the same vessel, likewise smaller 
and weaker, had disappeared, having been probably devoured by its com- 
panions. 
The older observers considered the Doris a hermaphrodite animal. 
But this opinion may be safely abandoned, by admitting the usual course 
of nature. The preceding union was on the 4th of October ; spawning 
followed next morning, though probably not its consequence. 
If the parent be vigorous, the spawn is deposited as the most regu- 
lar undulating logarithmic curve of several volutes. But it appears in 
small spiral masses if the parent be attenuated. 
The transparence of the body exposed the formation of the ovarium 
in clusters, as if occupying the whole cavity of the abdomen, towards the 
close of August. Yet the first spawning did not precede the 5th of 
October. The third on the 8th of October, consisting of seven entire and 
uninterrupted volutes ; and another of five, followed on the llth. This 
was succeeded on the 16th by four volutes, more perfect and regular, if 
possible, than any of the former, fig. 6. Now it was computed that the 
whole hitherto produced might have extended twelve inches in one un- 
interrupted line. Spawn appeared at four subsequent intervals until 
November 6. 
The orifice of the oviduct opens under the first branchial cluster on 
the right side. From hence the spawn issues like a coarse white thread, 
of albuminous consistence, studded throughout the diameter with ova. 
The extremity of the line first discharged being affixed, the parent re- 
cedes slowly and gradually in circumferential progression as expulsion 
of the thread continues, until the whole spiral figure is completed. But 
this is a very slow process, an hour being consumed in producing two 
volutions. | 
Here the diameter of the figure of the earlier spawn was six lines, 
