276 
bulletin of the bureau of fisheries. 
these writers seems to have found this variation of similar toothed claws much more 
common in the European lobster.® The history of development proves, as Stahr main- 
tained upon theoretical grounds, that the toothed claw represents the more primitive 
and the crushing claw the more modified type. Therefore it seemed natural to infer, 
as he did, that the anomalous symmetry in these weapons had been brought about by 
loss of a crushing claw and a subsequent reversion to the primitive toothed condition in 
the regenerated member which took its place. This would give us a lobster with sym- 
metrical toothed claws like the variation described. 
The converse of this, or the production of a new crushing claw in place of a toothed 
“forceps,” could not occur upon Stahr’s theory of regeneration, and hence he inferred 
that my report of a case of similar crushing claws in a lobster was an error. It was 
later at first rejected on similar grounds also by Przibram, who regarded the report as 
incredible and “worthy of being consigned to the realm of fishermen’s myths.” It 
should be added, however, that this objection was withdrawn in a later contribution 
(225), and neither Stahr nor Przibram are to be blamed, for my report was based upon 
the statement of a fisherman. Still, however great the inaccuracy of fishermen in 
biological matters, I have yet to find a lobsterman who could not tell a “club” from a 
“quick” claw. It now seems that the maligned fisherman, for once at least, was right, 
and he should get his dues even if earlier theories have to be revised, for Dr. W. T. 
Caiman, of the British Museum, has described a case of symmetrical crushing claws in 
the European lobster (45), and his account is accompanied by an excellent photograph, 
which he has kindly permitted me to use (pi. xxix). In all other respects this animal 
was a perfectly normal male. It was caught near Stromness, Orkney, and its living 
weight was 4 pounds 10 ounces. 
In a letter, under date of December 3, 1906, regarding this unique specimen, Doctor 
Caiman says : 
The correspondence between the two chelae as regards arrangement and size of the crushing tubercles 
is even closer than appears on the photograph, where slight differences of color have a little obscured 
the shape in one or two points. The differences are no greater than one would expect to find between 
the two sides of a normally symmetrical animal. In other respects the chelipeds are practically alike 
in size and shape, except that, as seen on the figure, the dactylus of the left is shorter than that of the 
right. The basal segments of the limbs show no trace of asymmetry, which is often associated with 
regeneration. 
To return to Emmel’s paper ( 93 ), we find that in two recorded cases, an 8j^-inch 
female and an 8-inch male, “crusher claws” were regenerated after amputation by 
autotomy of normal asymmetrical chelae. Emmel further records the capture at the 
Rhode Island experiment station in 1895 of a single adult lobster with similar “nipping” 
claws. When these were removed by autotomy two similar claws were also reproduced, 
but in this instance of the “nipping” type, like those cast off. 
While in the usual course of events regeneration of a large cheliped restores the 
normal asymmetry of an adult lobster, Emmel has clearly established the fact that it 
a Przibram (223) has reported a case of similar toothed claws in a specimen of the Norwegian lobster (Nephrops norvegicus) 
preserved in the Hofmuseum of Vienna. 
