132 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



Crustacea, I was unable to find that either Bateson, Faxon, or Her- 

 rick record an instance of a double extra claw arising from the third 

 segment or carpopodite. The only case at all similar to it is that of 

 a crayfish, Astacus fluviatalis; this most "unique" specimen dif!"ered, 

 however, from the present case, in that, instead of two there were 

 three extra chelae which arose from the carpopodite. (See Bateson, 

 No. 827.) 



S'pecimens Nos. 8 and 9. (Fig. 24-35.) 



The fact that in the four specimens out of over 3,000 lobsters which 

 were found with similar chelae (see specimen No. 4) the claws were all 

 of the nipper type emphasizes the point that it is extremely rare to 

 meet with a lobster with two ''crusher" claws. Indeed it has been 

 a matter of considerable doubt whether or not a lobster is ever found 

 with a crushing claw on each of the two "great chelae;" for in the 

 adult lobster the "great" claws are almost invariably asymmetrical 

 with reference to each other — the claw on one side being "nipper" 

 and the other a " crusher." On the other hand, in the young lobster 

 (i. e., in the fourth, fifth, and sixth stages) the two claws are alike 

 and similar to the nipping type; and the fact that in the rare in- 

 stances in which symmetrical claws have been found in adult lobsters 

 both were always of the "nipping" or embryonic type has created a 

 strong presumption that a "crushing" claw would not be developed 

 on each chela of this crustacean. 



Until a year ago the only case recorded of two crusher chelae on 

 the lobster was in a footnote to Herrick's ('96) description of varia- 

 tions in the form of lobster chelae: "I have heard of a single case 

 reported by a fisherman, where similiar crushing claws were developed 

 on both sides of the body" (p. 143). To Przibram, writing in 1901, 

 this seemed such an incredible phenomenon that, in view of the 

 theoretical reasons indicated in the preceding paragraph, he con- 

 cluded that: "Der eine Fall von einer Hautung beiderseitigen" 

 crushing-claw, von dem Herrick nur vom Horensagen durch Fischer 



