REPORT OF COMMISSIONERS OF INLAND FISHERIES. 49 



dominal segment. The appendages of the last may be seen budding 

 beneath the cuticle on the sides of the segment. Thus the tail-fan 

 has not changed from the first stage. 



The Third Larval Stage. 



The entrance into the third stage is marked not only by an increase 

 in the size of the young lobster, which now measures somewhat over 

 11mm. (less than half an inch), but in the further change of many 

 of the appendages. The general body form is much the same as 

 that of the two preceding stages, but for the increase in length of the 

 cephalo-thorax (relative to its depth) and the lessening in the con- 

 vexity of the dorsal surfaces of the same. The eyes have since the 

 first stage been drawn somewhat inward and backward, and are 

 now much smaller compared with the relative size of the body in 

 this stage. We here find also that there may often be one or more 

 post-orbital spines projecting from the carapace in back of the eye, 

 and one spine or more is often found on the dorsal side of the rostrum. 



Regarding the antennse, it is observed that, though the endopo- 

 dites of the first pair are in diameter much smaller than the exopo- 

 dites, the former have so increased in length that they project some- 

 what beyond the latter. The segmentation of both inner and outer 

 portions may be plainly observed at this period. The endopodites 

 of the second pair of antennse are developed in length somewhat 

 beyond the exopodites, which still retain their broad and leaf-like 

 form and the rim of setae about the inner margin. (Plates IX, XV.) 



The walking legs, maxillepeds, and chelipeds have undergone 

 another forw^ard shifting, so that the position of the chelipeds is 

 still nearer the normal or adult position. These large claws have in- 

 creased in size so that now in the third stage they are somewhat 

 stronger and larger in proportion to the size of the lobster. There 

 is yet no apparent difference between the left and right claws, a fact 

 which is first observable in a somewhat later stage. (Plate XVII.) 



During the earlier part of the third stage the exopodites of the 

 walking legs, chelipeds, and maxillepeds are highly functional. 



