NATURAL HISTORY OF AMERICAN LOBSTER. 
273 
moth lobsters generally. The cracker claw of this giant is remarkable for its swollen 
ovoidal form, its girth being 20 % inches, and for its worn and blunted tips; the blunt end 
of the “hand” is even recessive, the tubercular margin being convex as is frequently 
noticed in very large animals, and this in spite of the fact that the big molars are worn 
nearly flat. The worn-off end of the dactyl strikes about midway on the big distal 
tubercle, while the arrangement of the tubercles themselves is typical and essentially 
that given above; the propodus showing only two big “crushers,” with one small inter- 
mediate and two paired or double proximal tubercles. 
In the lock forceps of this specimen the hooked points are broken, rasped, and worn 
down, while its serrated margins are slightly convex, as is often the case in the fourth 
or fifth stage. The dactyl of this claw presents 7 to 8 primary spines. The huge, 
pyramidal lock spine of the propodus is much worn, and the first period distal to this 
bears 10 spines, having the formula: 1 + 1 + 2 + 4+2 = 10. Then follows a long and 
probably compound period of 17 spines; then a primary spine and several smaller ones 
opposite the “spur.” Thus, in this huge claw from lock to spur there are only three or at 
most four periods represented, as in all the younger stages hitherto discussed. This again 
illustrates the fact that while the procession of spines is constantly “on the move,” 
the “dental formulae” for the toothed claw never being identical for any two successive 
molts, the losses are so well balanced by the gains that the toothed claw, which attains 
its characteristic form from the fourth to the seventh molt, remains essentially unchanged 
throughout life. 
We have seen how the toothed type of claw, which Stahr considers an ornament 
fitted to please the “aesthetic sense” of these animals, has arisen, but the wonder is 
not that the teeth are arranged in periods of eight, but that they are developed in order 
at all. The problem is similar to that of the orderly arrangement and appearance of 
the paired mesentaries of certain coral polyps, and fundamentally the same as that 
of the orderly development of the parts of all organic bodies, concerning the mechanics 
or the regulative control of which nothing is definitely known. 
When we consider the known structure and development of the great claws in 
relation of the known habits of their possessor, we find no warrant in considering them 
as an “ornament” or in any other light than that of most efficient tools and weapons, 
chiefly for defense, for the capture of prey, for rending it in pieces, and afterwards for 
handing over the edible parts to the grinding mechanism which begins with the mouth 
parts and ends in the stomach. The developmental history of the lock forceps and its 
periodic teeth, as narrated above, renders any criticism of Stahr’s fantastic theory, on 
the ground of comparative psychology, superfluous. 
On the inner margins of the great claws appear certain prominent spines (fig. 2, 
pi. xxxvii up. ser., and /. ser.), which are very regular in form and position, but vary 
somewhat in number. They consist of an upper series of 4 to 6 stout spurs curved 
upward and forward, and a lower of 1 to 3 teeth of lesser size, alternating with the first, 
and bent downward and forward. They probably originate from a single series, by 
displacement. They are eminently protective, while the proximal and often double 
spur on the upper side may act as a buffer when the claw is folded inward. Greater 
48299° — Bull. 29 — 11 18 
