180 



BULLETIN OF THE UNITED STATES FISH COMMISSION. 



Before molting the animal was of a dark umber color and very sluggish. Imme- 

 diately after this ecdysis (the seventh in number) the whole body was translucent, the 

 general color being reddish-brown, with a slight greenish tinge on the carapace. The 

 large claws were a bright terra-cotta color. There was a prominent whitish crescentic 

 spot immediately behind the cervical groove and the three characteristic tendon marks 

 on each side of the carapace were as prominent as in the sixth stage. (Compare plate 

 24.) The pleura of the first abdominal somite were snow-white, and the uropods of the 

 tail-fan were tipped with cream color. 



The lobster after the seventh molt keeps steadily upon the bottom, in walking- 

 over which it uses chiefly the last three pairs of thoracic legs. The large claws and 

 smaller chelate legs next to them are extended forward in front of the head, although 

 the latter appendages are occasionally used for locomotion. A very slight differentia- 

 tion in the large chelae is noticed, but in the eighth stage the difference is marked. 

 At about the time of the seventh ecdysis the right antennary flagellum was lost; 

 eight days later it appeared, in the process of regeneration, as a short spiral coil; 

 this continued to grow, and after the eighth molt, which occurred on the 8th of 

 August — an interval of two weeks from the last — it was about its normal size. 



At the seventh stage pigment has been deposited below the enamel layer of the 

 cuticle in an amount which, though at first very slight, increases with every molt, and 

 the color pattern becomes more and more complex. In the eighth stage the general 

 color is deep reddish-brown, with olive tints. The characteristic tendon marks and 

 cream-colored spots are present. There is a dorsal light-green median stripe on the 

 carapace, very much narrower than when first seen in the fourth stage. 



This lobster had uudergone no appreciable change by the 23d of August, but 

 when next examined, September 22, it measured 29.5 mm. In the interval of thirty 

 days it had undoubtedly molted twice and was in the tenth stage. The first abdominal 

 somite has very delicate, white appendages, which are distinctly two-jointed and raised 

 from the surface to a nearly vertical position. 



Lobster No. 5 (table 35). — This lobster was hatched about May 25, and when 

 isolated, on August 1, it measured 24 mm. It was probably in the ninth stage and was 

 about 67 days old. The general color was dark green, touched with brown; large 

 chela' olive-brown, reddening toward the extremities, with glistening white tips; the 

 under side was a tint lighter. The uropods and telson are whitish, bordered with 

 reddish-brown. The contents of the intestine can be seen through the slightly trans- 

 lucent shell. Tendon marks on the carapace are prominent, as in the other cases 

 described. 



Some measurements of this lobster are as follows: 



Measurements of lobster No. 5, in ninth stage. 



Length 



Length of carapace 



Greatest width of carapace 



Length of antennary fiagelluni. 



Length of large chela on either side... 

 Greatest breadth of chela of one side. . 

 Greatest breadth of chela of other side 



Millime- 

 ters. 



24 

 31 



5 

 23 



9 



3 



2.5 



In the smaller of the two claws the extremities are nearly straight; in the larger 

 the "fingers" are more bent, and each bears a large tubercle at about the middle of 

 the occludent margins. 



