274 



BULLETIN OF THE BUREAU OP 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 estabUshed, 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 tjip right side as upon the left, 

 without distinction of sex, as shown by the following table, in which 2,433 individuals 

 are recorded: 



Table 7. — Showing Variation in Position op Big Claws. 



I have shown that in Synalpheus brevicarpiis,'' 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 CoutiSre 

 and our combined results are tabulated below.' 



Table 8. — Showing Position op Big Claws in Broods op Synalpheus. 



^ "'In the Carabi and in the Carcini the right claw is invariably the larger and stronger. For it is natural to every animal to 

 use its right side in preference to its left. In the Astaci alone it is a matter of chance which claw is the larger, and this in either 

 sex." Aristotle: The parts of animals; translated by W. Ogle, London, 1882. 



6 Herrick, F, H.: Alpheus: A study in the development of Crustacea. Memoirs of National Academy of Sciences, vol. 

 V. ch, V, 4th mem., p. 370-463-1-, pi. 1-38). Washington, 1892. 



«Coutifere, H.: Les "Alpheidae", Morphologie exteme et interne; Formes larvaires; Bionomie. Annales des Sciences natu- 

 relies. Be s6r., Zoologie. t. i,x, p. i-iv, 1-560, pi. 1-6, text fig. Paris, 1899. 



dThe exact number in this brood was uncertain, but all that were preserved were left-handed. No. 1-4 were observed by 

 the writer, no. 5-8 by Coutifere. No. 1-3 refer to Synalphetis brevicarpui, no. 4-8 to the smalJ Synalpheus longicarpus which 

 aboim^ds in the big black Hircvma sponges along shore. 



