1273 THE HORSE FOOT CRAB. 
hatched the young burrow like the adult; hence the rare- 
ness of an opportunity to witness the casting of the skin. 
Hoping to continue observations upon the dii of my in- 
teresting family the ensuing year the jars were carefully put 
away. Little regard, however, was paid to temperature, 
which, on several occasions, went down to the freezing point. 
On the 3d of May, 1870, I emptied the jars to see how my 
charge was getting on, when lo, not one of the last year's 
hatching was alive! but wonderful to say at least a dozen 
little fellows, all hatched this spring, and all alive, had taken 
their place. With these were also at least thirty eggs, in 
different, but all in advanced, stages of incubation. In some 
of them the young could be plainly seen revolving. The 
fact was these eggs had been at the bottom of the hatching 
jar, and had never had any contact with the sunlight. At 
once, not without some misgiving as to the result, the 
proper provision was made to complete the incubation, 
namely, new sea-water, clean sand, the eggs put on top, and 
all set in a favorable place. With an eedinary hand lens 
the progress of incubation could be observed daily. At 
half-past four o’clock on the afternoon of May 11th, before 
. my eyes, a new-born baby Limulus left the egg. Just think 
of it—these eggs are within two weeks only of being a year 
old! And then how remarkable are these facts also—those 
eggs were partly incubated last summer. Hence there has 
been not only a remarkable retardation of development, but 
also an actual arrest of the same for seven or eight months 
without sacrificing life. Query: is there any connection 
here with that indomitable persistence of being, which in 
the Divine will has carried this comprehensive type through 
the many Eons of existence, wherein has been unrolled so 
slowly the life plan of the Entomostraca, from that initial 
Trilobite of the Pre-siluria to our Limulus of these latter 
days? 
It has been hinted already in this article that at different 
stages of its life the larval Limulus made a different impress 
