244 The American Naturalist. [Mareh, 
had previously given the name Gonerichthus is the young of Gono- 
dactylus. 
The account of the various species of Alpheus is most detailed and 
one of the most striking facts brought out is that the same species in 
different localities may have an almost totally different development. 
Thus, in the Bahamas, Alpheus heterochelis? hatches from the egg with 
all its appendages functional as far back as the third pair of maxilli- 
peds, while the pereiopoda 1, 2, and 5 are bud-like rudiments, and the 
joint between abdominal segment 6 and the telson has not appeared 
and no pleopoda are outlined. At Beaufort, N. C., the species is much 
more advanced before leaving the egg, but the stage at which it hatches 
is not directly comparable with any stage in the life history of the 
Bahaman form. At hatching all the appendages of the adult are 
present, and all become functional after the first molt. In the Bahamas 
there is a long series of larval stages, while at Beaufort there isa great 
acceleration, and even this is not all; the Beaufort stages are so mod- 
ified that at no time can exact parallels be drawn between them and 
the more southern form. In the Bahamas there are three, then four, 
then five, and then seven schizopodal feet with functional exopodites, 
while at Beaufort there are never more than three. Yet these differ- 
ent types of metamorphosis result in the production of adults which 
are almost exactly alike. It must be noted that Packard has described 
still another type of development for what he regards as the same spe- 
cies at Key West. For the details of the development of the different 
species of Alpheus studied we have but little room; those interested 
must seek the memoir itself. The segmentation in A. sauleyi and A. 
heterocheelis is typical centrolecithal, with the formation of yolk pyra- 
mids ; in A. minus it is irregular and has no yolk pyramids, but the 
statement (pp. 427 and 457) that it is amitotic deserves further inves- 
tigation. All of the nuclei resulting from segmentation migrate to 
the surface and there by delamination they produce “ wandering cells” 
which pass into the yolk and give rise to both mesodermal and ento- 
dermal structures. The subject of degeneration of certain nuclei is 
also very interesting. Dr. Herrick has carefully followed the increase 
of nuclei in the various parts of the embryo, and has plotted curves 
illustrating the distribution of primary yolk nuclei, of wandering cells, 
*There isa great diversity in this memoir as to the spelling of various 
scientific terms. Thus we have usually heterochelis regardless of the fact 
that Say, who described the species, wrote heterochelis; Alpheus minus 
appears as minus, minos and minor; centrolecithal sometimes as centroly- 
-cethal; Lucifer.as Leucifer. 
