NOTES ON THE EMBRYOLOGY OF LIHULUS. 
527 
described and figured by Dr. Packard as existing outside^the 
“ germinal area/’ and am of the opinion that it does not 
exist, as usually metameric segmentation does not exhibit 
itself in epiblast alone, and the mesoblast has not yet extended 
itself so far. 
As was noticed by Dr. Packard, between this and the next 
stage a second moult takes place, the cuticle being lifted up upon 
the feet as shown in fig. 11. Now motion begins, and the 
movement of the limbs, at first very slow, tears this second 
cuticle, the remains of which can be seen until the time of 
hatching inside the “ vicarious chorion.’ 5 
In the next stage necessary to be mentioned (fig. 12) a limu- 
loid appearance is visible. The body is elongated and the 
abdomen is differentiated, and it and the cephalothorax are dis- 
tinctly segmented, six somites being visible in the latter and 
eight in the abdomen, the ninth or telson not being separated 
from the preceding segment. The cephalothoracic limbs are 
jointed and the chelae outlined, while the peculiar whorl of 
spines on the sixth pair is already formed. The flabelliform 
appendage on the outer side of the coxa of the same pair and 
the metastoma are also visible. In the abdomen the oper- 
culum and the first branchial appendages are well developed, 
and the gills upon it are beginning to be formed. The second 
branchial appendage is just appearing. 
Fig. 14 corresponds so closely with Dr. Packard’s (’72) fig. 24 
that there is no necessity for describing it here. I would, how- 
ever, state that his representation of the appendages (a matter 
of no great morphological importance) is extremely faulty, and 
in 24, a, the eye is much too remote from the margin. At this 
stage specimens just killed with alcohol show the posterior 
portion of the nervous system very plainly through the integu- 
ment, but I have not been able by surface views to show 
exactly the innervation of the anterior pair of limbs. This, 
however, is to be the less regretted, as my sections settle this 
point. I would in passing state that Dr. Packard’s (’80, a) pi. 
v, fig. 8, cannot be relied upon as proving that the first pair 
are post-oral ; the stage is too late for that demonstration. 
