30 
WILLIAM KEITH BROOKS 
1882, and his ''Report on the Stomatopoda/^ which appeared as 
part of the sixteenth volume of the Scientific results of the Chal- 
lenger Expedition in 1886. In the former work, we are told that 
in April 1880, he found at Beaufort ''a single Lucifer with two 
eggs attached to one of its appendages,*' and that he was *'led 
by the great importance and interest of the subject to make every 
effort to trace its life-history." Success came only after months 
of repeated failure, when at last he could say with evident satis- 
faction: ''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 crusta- 
cean with the metamorphosis of which we are more thoroughly 
acquainted than we now are with that of this extremely interesting 
genus." Not only did he discover that Lucifer emerged from the 
egg as a true Nauplius, but what was even more novel, that the 
egg underwent a total and regular segmentation, and gave rise to 
an egg-gastrula of the invaginate type. After giving an exhaustive 
analysis of the developmental stages of Lucifer, and comparing 
its successive appendages with those of other representative Mala- 
costraca, he concludes that the three-jointed Nauplius larva repre- 
sents a true ancestor, that there is essentially but one kind of 
homology presented by metameric animals, and that, therefore, 
the remote ancestor of the Crustacea does not represent a com- 
munity of once independent parts. 
The monograph on the Stomatopoda is distinguished by the 
great ingenuity shown in classifying all of the known larvae of 
this sub-order, and in tracing them to their proper genera, for 
he had no living material to work with, excepting the two species 
from the southern coast of the United States, Squilla empusa and 
Lysiosquilla excavatrix, which he had previously studied, and 
which he used for exact comparisons so far as possible. He said 
of the collection submitted to him, that while it contained only 
fifteen species of adults, eight of which were new, it was very rich 
in larvae. In speaking of the eggs, he remarked that since they 
were not carried about by the female, attached to her body or 
appendages, as is the rule in the higher Crustacea, they quickly 
