74 STALK-EYED CRUSTACEA. 
they show a little when the animal is viewed from above. The basal seg- 
ment of the antennz, moreover, is more exposed from above than it is in 
the more typical species of Munida. 
The lateral rostral spines, or supraocular spines, are curved upward more 
than the median rostral spine, and the three are nearly parallel; the lateral 
spines reach about half way to the tip of the median; all three are micro- 
scopically spinulose on their upper edge. There are two pairs of spines on 
the anterior part of the gastric region in line with the lateral rostral spines. 
Of these two pairs the anterior is the larger. There is also a longitudinal 
line of spinules in the median line between the two pairs just spoken of. The 
arrangement of the other spines on the anterior portion of the carapace will 
be best understood by reference to the figure on Plate XVI. The cardiac 
area is somewhat sunk below the level of the surrounding parts, its anterior 
margin is denticulated, with a larger spine on each side. The lateral mar- 
gins of the carapace are armed with ten or eleven spines, the one on the 
antero-lateral angle being the longest. The second abdominal segment is 
ornamented with a transverse row of eight small spines. The other abdomi- 
nal segments are normally destitute of spines, but in a few of the many 
specimens before me there are two or four small spinules on the third seg- 
ment. The pleure of the third, fourth, and sixth abdominal segments are 
acute, the rest blunt. The eyes are large and are provided with rather long 
cilia on the edge of the cornea. The basal joint of the antenna is armed 
with a long and sharp spine which reaches forward beyond the eyes; the 
second joint also has a long spine on each side. The chelipeds are long and 
hairy ; the merus, carpus, and basal part of the propodite are spiny, the 
fingers long, slender, the cutting edges straight and finely spmulous.* The 
ambulatory appendages are setose, the upper and lower edges of the merus 
are spinulose, and there is, moreover, a row of spinules on the outer surface, 
this external line of spinules being best developed on the proximal end of the 
segment; the carpus is armed with small spines on the upper margin and 
* In some of the males the chela is broader than in others, and the basal part of the propodal digit is 
curved so that there is a distinct gap at the base of the fingers, with one or two rather prominent teeth on 
the base of the cutting edge of the dactylus. This difference in the form of the chela is generally found among 
the males of the different species of Mwnida, and has been referred to by Henderson (Challenger Anomura, 
p- 127), as a case of dimorphism. I have elsewhere (Amer. Journ. Sci., 3d Ser., XX VII. 42-44, 1884.) shown 
that the two forms of the male in the genus Cambarus are alternating stages in the life of the same indi- 
vidual, one phase being assumed during the breeding periods, the other during the intervening seasons or 
sexual quiescence. Jules Bonnier (Comptes Rendus de I’Acad. Sci., CXI. 987, 1890) has shown that the 
same condition of things exists among the Amphipoda. I have no doubt that the two forms of the male in 
the genus Wunida are to be explained in the same way. 
