110 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 



fore, to be regarded as the representative of the normal meropodite, 

 while the left branch (m^ is the extra or abnormal structure. 



The remaining distal segments (C, D, I) of the normal chela pre- 

 sent the usual characters, and with the claw (D I) opening in hori- 

 zontal plane. The tips of the claw are bent slightly downward ; a 

 condition which may have been caused by a cramped position of 

 these parts while hardening after the moult. At first sight it is not 

 so clear whether this claw is a ''nipper" or "crusher;" in its general 

 form it is rather elongated and slender, like a nipper; but on the 

 other hand, there is an almost entire absence of tactile hairs, and the 

 dentition is characterized by the presence of "crusher" teeth. 

 This claw is, therefore, of the crusher type, although in some respects 

 it may be regarded as transitional between a nipper and crusher.* 



Going back now to the abnormal part of the meropodite (m'), 

 it is clearly evident that the next distal segment or carpopodite 

 C'(R+L), is morphologically double. It is very massive and more 

 than twice the size of the corresponding normal segment (c); a 

 longitudinal groove (g) divides it into two equal sections; the outer 

 surface of each of these sections is set with a group of spines, and 

 distally each half forms a true joint with the corresponding propo- 

 dites, P'R and P'L. Each half of this segment, with its joint and 

 spines, is, therefore, homologous with the normal carpopodite. This 

 double character of the abnormal carpopodite can also be traced 

 back into the meropodite. 



The morphological characters of the two extra claws (R'-f-L') 

 may be indicated in a word, as these claws are almost exact mirror 

 images of each other. In general form the dactyls and indices of 

 each claw are almost identical; the dentition consists of large 

 tubercle-like teeth, with double teeth set near the angle of the jaw 

 on each index; tactile hairs are almost entirely absent. Further 

 details are not necessary, for it is evident at a glance that these two 

 claws are both of the "crusher" type of chelae. 



In size these two extra claws are somewhat larger than the third 



* A phenomena not uncommon in the lobster, especiahy in case of regenerated chelae. See 

 Emmel '06. 



