274 
BULIvETIN of the bureau of fisheries. 
attention, however, is called to the serrated jaws of the forceps themselves, owing to 
the origin of their teeth by interpolation in the way described, and to the periodicity 
thus established, but the biological significance of one set of spines may be as great as 
that of the other. 
VARIATION IN THE POSITION OF THE GREATER FORCEPS. 
As was long ago remarked by Aristotle, ® it seemed a matter of chance whether the 
crushing claw were on the right or left side of the body, but this is not altogether the 
case. The large claw occurs about as frequently upon tXe right side as upon the left, 
without distinction of sex, as shown by the following table, in which 2,433 individuals 
are recorded : 
Tabi.e 7. — Showing Variation in Position of Big Claws. 
I have shown that in Synalpheus hrevicarpus p of the Bahama Islands, where the 
large hammer claw can be recognized even before the animal is hatched, the members 
of a brood are either right-handed or left-handed, that is, have the hammer on the same 
side of the body. This seems to be a case of direct inheritance from the parents, though 
not enough data were collected to settle this point. 
Since the issue of that work my early observations have been extended by Coutiere 
and our combined results are tabulated below.® 
Table 8. — Showing Position of Big Claws in Broods of Synalpheus. 
raltc 
■S of Nat: 
is the larger, 
lal Academy of Sci< 
“•'In the Carabi and in the Carcini the right claw is invariably the larger and stron 
use its right side in preference to its left. In the Astaci alone it is a matter of chance w 
sex.” Aristotle: The parts of animals; translated by W. Ogle, London. 1882. 
*> Herrick, F, H.: Alpheus; A study in the development of Crustacea. 
V. ch. V, 4th mem . p. 370-463+, pi. 1-38). Washington, 1892. 
eCouti&re, H.: Les “ Alpheidae”, Morphologie exteme et interne; Formes larvaires; Bionomie. Annales des Scien 
relies. 8« s&t., Zoologie, t. lx, p.Viv, 1-560, pl. 1-6. text fig. Paris, 1899. 
dXhe exact number in this brood was uncertain, but all that were preserved were left-handed. No. 1-4 were obs 
the writer, no. 5-8 by Coutibre. No. 1-3 refer to Synalpheus brervicar pus, no. 4-8 to the smal! Synalpheus longicarp 
abounds in the big black Hirctnia sponges along shore. 
