‘186 E. A. AnDREws, 
firmly hold the female, so that no special chelae would seem neces- 
sary. In this position the pleopods of the female might come against 
the spermatophore mass as it was being applied, and we noted on 
one female some black solidified secretion, like tar, adhering to the 
setae on the anterior edges of the first pleopods, as if an excess of 
the material used in forming the large spermatophore masses, which 
were present. 
While the specialized claws are found only in the females and 
are hence thought to pertain to female functions only, the males of 
Paribacus show interesting suggestions of similar celaws of no use 
apparently. 
Some males have in place of the thumb of a claw on the fifth 
leg a minute scar or repressed tubercle but some males have a 
slender tubercle as much as 2 mm long in the place of a thumb. 
This outgrowth of the shell is, moreover somewhat flattened on the 
face toward the last segment of the leg where it might be touched 
by that segment in extreme flexure, Fie. E. 
Careful examination of this little tuberele shows not only that 
it has the horny tip of a terminus of a leg and is thus like the 
thumb of the female claw, but that its flat face toward the distal 
segment of the limb has, as indicated in Fig. G, a decided suggestion 
of thumb structure. This small face is not only flat and bluntly 
pointed like the thumb but bears a rim, however imperfect, and 
within this a number of setae forming on one side at least a row 
paralleling the rim. On the other side, however there are as many 
suppressed setae or mere shrunken semi-horny eminences in place 
of setae. The setae moreover are plainly serrated along one face, 
but this tendency to side outgrowths is strongly marked thoughout 
these animals, both male and female, which are largely covered with 
peculiar nodular elevations fringed by setae that are more or less 
pinnate. On the whole this male limb may be said to suggest the 
claw of the female by exhibiting a minute thumb of very imper- 
fect formation but nevertheless homologous with ihe thumb of the 
female. In the female the thumb is useful, in the male its suggested 
homologue is of no use, as such. It would appear to have been 
perfected in the female and somehow more or less suggested in the 
male: indicating the essential identity of the two sexes with only 
the more or less complete suppression of some factors in each sex. 
A reexamination of male specimens of Panulirus shows that 
while most of them have no suggestion of a claw whatever, yet some 
