62 
MR. W. K. BROOKS OK LUCIFER: 
stating that I have fortunately been able to complete his observations upon Lucifer, 
and to furnish a very perfect account of its entire metamorphosis, as well as a few 
important facts with reference to its development in the egg. 
At the end of April, 1880, I found a single specimen of Lucifer with two eggs 
attached to one of its appendages, and I was led by the great importance and interest 
of the subject to make every effort to trace its life-history. For four months I met 
with no success whatever, but about the 1st of September I found a few advanced 
larvae, and traced them to the adult, and I then succeeded in finding earlier stages 
and tracing them as far as the stages which I had previously found, but it was not until 
the last week of my season at the sea-shore that I succeeded in hatching the Nav/piius 
from the egg, and the last gap in my series was bridged by a moult which occurred 
only a few hours before my departure. 
As the result of my four months’ efforts I can now state that I have seen the eggs 
of Lucifer pass out of the oviduct. I have seen the Nauplius embryo escape from the 
same egg which I had seen laid, and I have traced every moult from the Nauplius to 
the adult in isolated specimens. There is therefore no Crustacean with the meta¬ 
morphosis of which we are more thoroughly acquainted than we now are with that of 
this extremely interesting genus. 
Not only is it true, as W jllemoes- S uhm has pointed out, than Dana’s Erickthina 
demissa is a larval stage of Lucifer, but that Dana’s Sceletina cirmata is a later stage 
in the same series, while some of the forms which he includes in his genus Fur cilia 
are also, in all probability, Lucifer larva). 
The occurrence of a free Nauplius stage of development in the life-history of one of the 
higher Crustacea is a matter of such profound significance in the scientific discussion 
of the phenomena of embryology in general, that it can hardly be accepted without 
question so long as there is any possibility of error. Two of the observers who have 
testified to its occurrence have based their conclusions upon evidence which would be 
perfectly satisfactory in any ordinary case, but as they did not actually trace all the 
stages of development their statements do not stand, the severe analysis which the 
importance of the case demands, arid certain naturalists have therefore refused to 
give them unqualified acceptance. 
The third observation was made so many years ago, and the larva is so briefly 
described, that it would not be safe to assume, in the absence of all corroborative 
evidence, that it is a Nauplius at all. 
In December, 1838, Dana found in the harbour of Bio de Janeiro great numbers of 
specimens of a Schizopod, which he described (‘ United States Exploring Expedition 
during the Years 1838-1842,’ under the command of Charles Wilkes, U.S.N., 
vol. xiii., part i., p. 654) as Macromysis gracilis. In the brood-pouches of some of 
his specimens he found an abundance of eggs and developing embryos, several of 
which are shown in his plate 45, fig. 5. He made no careful study of their structure ; 
his notice of them in the text is only a few words; and his figures are very small. 
