Lep eophth eirus dissimulatus^-LEWis 
233 
of the outer surface and six are borne on the 
distal surface. The one-segmented, dactyliform 
endopodite is attached to the inner distal sur- 
face of the protopodite. The greatest length of 
the segment is about two-thirds of the length 
of the exopodite, its width about one-half of its 
length. The endopodite is tapered slightly to- 
wards the rounded distal end which bears five 
lightly plumose setae; an additional lightly plu- 
mose seta is present on the middle of the inner 
margin. 
As with the first thoracic leg, the second 
shows a rather distinct transition in the moult 
from the second chalimus to the third. The ap- 
pendage in the third chalimus (Fig. 19 d) has 
changed from the rather generalized condition 
in the second chalimus to a condition which, 
with some exceptions, resembles that of the 
adult. 
The protopodite of the second thoracic leg of 
the third chalimus is two-segmented. The first 
segment is narrow and forms a strip between 
the sternal plate and the second segment. A 
single plumose seta arises from the inner surface 
of the first segment. The second segment is 
broad and flattened, its greatest width is almost 
three-fourths of the greatest length, the outer 
margin is irregular, and the inner margin is 
convex. The exopodite, which is attached to the 
outer distal surface, is two-segmented. The 
length of the first segment is slightly greater 
than that of the second, and the greatest width 
is approximately two-thirds of the length; the 
lateral margins are irregularly convex. A long 
spine is present on the outer distal surface and 
is directed distally; the length of the spine is 
slightly less than two-thirds of the segment 
length. The second segment is slightly longer 
than wide, and the proximal end is narrower 
than the distal; both of the lateral margins and 
the distal margin are distinct, not continuous, 
and are irregular; the outer lateral surface bears 
four spines on the distal one-half of the segment. 
The proximalmost of the four spines is short 
and directed distally and laterally; the second 
spine is directed in the same manner as the 
first but is considerably longer; the third is 
directed laterally, curves distally, and is about 
the same length as the second; the fourth or 
distalmost spine is directed laterally and is more 
strongly developed than the preceding three. 
The endopodite, attached to the inner distal sur- 
face of the protopodite, is also two-segmented. 
The first segment is approximately two-thirds as 
wide as long and is curved inwards, the outer 
lateral margin being much longer than the inner 
and convexly curved. The second segment is 
slightly less than IVl times the length of the 
first and is longer than wide; both of the lateral 
margins are flatly convex and distinct from the 
distal margin, which is irregularly rounded. Both 
the exopodite and the endopodite bear setae, as 
indicated in Table 3. 
The second thoracic leg of the fourth chal- 
imus (Fig. 19e) is similar to that of the third 
chalimus. There has been some expansion of 
the protopodite segments and the first exopodite 
segment. The setae appear to be more plumose 
and, in general, the armature is more like that 
of the adult. 
The second thoracic leg of the fifth chalimus 
(Fig. 19/) is similar to that of the preced- 
ing stage although changes have occurred in 
the shape and the armature. The protopodite is 
two-segmented, the first segment short, being 
approximately one-third the length of the sec- 
ond segment; the width of the first segment is 
approximately three-fourths of the length. The 
outer margin of the first protopodite segment 
is longer than the inner, the proximal margin 
is angled, and the distal is straight. Further, the 
outer proximal surface of the segment has a 
small knoblike projection that articulates in a 
C-shaped depression in the end of the sternal 
plate (not shown in the figure), and the inner 
margin bears a single plumose seta. The second 
segment is swollen distally, the greatest width 
of the distal region being approximately four- 
fifths of the greatest length; the outer lateral 
margin of the segment is irregular, the inner 
broadly convex. The exopodite is still two-seg- 
mented, the first segment slightly longer than 
the second. The outer margin of the first seg- 
ment is convex, and the inner margin is slightly 
irregular. The outer distal corner of the first seg- 
ment bears a long, distally projecting spine that 
extends to the distal region of the second seg- 
ment. The second segment is palm-shaped, being 
wider distally than proximally. The greatest 
width of the segment is approximately two- 
thirds of the greatest length; the outer lateral 
margin is irregular and bears three strongly- 
