EEPOET OX THE STOMATOPODA. 
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increased in size and in numbers. The sides of the carapace are folded down over the 
body more than they are in the younger larvae, and the median dorsal spine is relatively 
shorter. The appendages of the third, fourth, and fifth thoracic somites are represented 
by buds, as well as the fifth abdominal appendages, and the three last thoracic somites 
are now longer than those in front. While I obtained a number of specimens of this 
stage I found only one older one, which moulted, before I had an opportunity to draw it, 
into the young Lysiosquilla excavatrix, shown in PI. X. fig. 13, although I was able to 
make from the moulted skin the drawings of the carapace and telson which are given 
in figs. 14, 15, and 16, of PI. X. 
Although this larva, the carapace of which was Ajj i n °h long on tbe middle line, 
including the rostrum, and inch wide between the bases of the postero-lateral 
spines, is many stages older than the one last described, the differences are so very 
great that I at first doubted whether they could belong to the same series, but the 
consecutive series of stages in the growth of the closely related larva which is described 
in the next section furnishes satisfactory proof that this is the case. The antero-lateral 
and dorsal spines are now very short, although the rostrum and postero-laterals are of 
about the same relative length as before, and none of the marginal spines were visible 
with the liand-lens under which the drawings were made, except one in front of the base 
of each postero-lateral and one in front of this by one-third of the distance to the small 
antero-lateral. Tbe telson (fig. 16) is now nearly rectangular, a little (-£) wider than long, 
with very long submedian spine, and a nearly transverse but notched posterior border 
carrying thirty-six small secondary spines with very minute spinules between them. As 
compared with the submedians the other marginal spines are very small ; the laterals 
are posterior to the middle line and have each a small spinule internal to the base, 
and one of the three secondary spines which were present in the younger larva has 
disappeared, while the second is very small, and the third much smaller than the 
intermediate. The change which takes place between this stage and the next, in the 
shape of the telson, is fully as great as the difference between the telson at this stage and 
that of the very young larva, as immediately after the moult the young Lysiosquilla has a 
telson essentially like that of the adult shown in PL X. fig. 8, transverse, and about twice as 
wide as long, with no secondary spines, and with all six marginal spines on the transverse 
posterior border, and the submedians united in a single median process, as shown in fig. 13. 
I am inclined to believe that a small Erichthoidina larva, which is occasionally, 
although very rarely, found on the eastern coast of the United States, is the larva of this 
species. Faxon has found one of these larvae at Newport, R.I., and he has figured it in 
pi. viii. figs. 11 and 12 of his selection from Embry ological Monographs. 1 Through the 
courtesy of Professor Baird I have also had an opportunity to examine a sketch of another 
specimen which Professor S. J. Smith obtained at the United States Fish Commission 
1 Bull. Mus. Comp. Zool., vol. ix. 1, 1882. 
