130 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



It should be added, however, that while the present abnormal 

 claw is apparently the first case of this kind recorded for the lobster, 

 a few cases of somewhat similar deformities have been found among 

 other Crustacea (see Bateson, 528-530). 



Specimen No. 4. (Fig. 4.) 



It will be recalled that this specimen was described as a normal 

 claw with two extra indices and an extra double dactyl arising from 

 the normal index. This form of abnormality is very rare. Bateson 

 describes a number of cases among crabs and lobsters in which two 

 extra indices alone arise from the normal index, but there seems to 

 be no record of two extra indices plus a double extra dactyl. 



Specimen No. 5. (Fig. 5.). 



This is a most remarkable case of the "triplication" of chelae. 

 Apparently the only recorded specimen which approaches it is the 

 right chela of a lobster described by Faxon (Plate II, Fig. 6). In 

 Faxon's specimen the meropodite divides distally into two parts, 

 each bearing an articulated appendage. One of these two branches is 

 a normal chela, but the morphological character of the abnormal 

 branch remains a question. The carpopodite of this latter structure 

 is not normal in form, "but is slenderer, subcylindrical, and much 

 more spiny." It "bears at its distal extremity an abortive propodus 

 in the shape of a small stump-like segment, bifurcated at the end and 

 armed with a blunt spinous tubercle on its inner margin" (p. 263). 

 Interpretations of this abnormal and rudimentary structure differ; 

 Bateson is inclined to consider it as "morphologically a double 

 structure" (p. 536), and, consequently, that the whole limb may be 

 a triple chela. But Faxon does not regard this extra structure as 

 double, and thinks that in this specimen we have an approach to 

 a duplication, rather than a triplication, of chelae. 



At any rate, in our present specimen there can be no question as 

 to its triple character, at least as far down as the meropodite if not 



