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228 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [ 
C.—THE METAMORPHOSES OF THE LOBSTER, AND OTHER 
CRUSTACEA.—BY S&S. I. SMITH. 
Most of the larger crustaceans of our coast, whatever may be their 
habits when adult, are, in the early stages of their existence after hatch- 
ing from the eggs, essentially free-swimming animals, living a large part 
of the time near the surface of the water. In this stage they are con- 
stantly exposed to the attacks of other predaceous animals, and, as they 
occur in vast numbers, afford food for many valuable fishes. They are 
most abundant at the surface in calm, clear weather, and they especially 
resort, like the young of many other marine animals, to spots and streaks 
of smooth water where the tidal currents meet. 
Very little has yet been written upon the forms or habits of the young 
crustaceans of our own coast; but,in connection with the investigations 
carried on in Vineyard Sound and Buzzard’s Bay, a great amount of 
material for such work was collected. This material has not yet 
been fully studied, and only a sketch of some of the more important re- 
sults is presented in this report. During the few weeks in June and 
July, in which I was myself at Wood’s Hole, the time was so fully occu- 
pied in collecting, that very little time was left for studying the animals 
while alive; hence most of the observations which follow, except ocea- 
sionally those on color, have been subsequently made from specimens 
preserved in alcohol. While at Wood’s Hole, I was much assisted in 
obtaining these young animals by every one then associated there in the 
work of the commission; and I would especially acknowledge such 
assistance from Dr. W. G. Farlow, Mr. V. N. Edwards, and Capt. John 
B. Smith. After I left, the collecting was kept up as before, and many 
valuable notes were made by Professors Verrill and J. E. Todd. 
Special attention was given to the early stages of the lobster, as per- 
haps the most important crustacean found on our coast, and I have gone 
more fully into the account of its early history than that of any other 
species. As this will serve as an example to illustrate the development 
of most of the other Macrourans, it is presented first. 
Numerous specimens of the free-swimming young of the lobster, in 
different stages of growth, were obtained in Vineyard Sound during 
July, but it was too late for any observations upon the young within the 
egg. This deficiency was partially supplied by a few observations at 
New Haven in 1872. Eggs taken May 2, from lobsters captured at New 
London, Connecticut, had embryos well advanced, as represented in fig. 
4, In this stage the éggs are slightly elongated spheroids, about 2.1 
in the longer diameter, and 1.9™™ in the shorter. One side is rendered 
very opaque dark green by the unabsorbed yolk mass, while the other 
shows the eyes as two large black spots, and the red pigment spots on 
the edge of the carapax, bases of the legs, &c., as irregular lines of 
pink markings. 
In a side view of the embryo, the lower edge of the carapax (d, figure) 
