TTITC AMERICAN LOBSTER. 



181 



The animal hides among the stones at the bottom of the aquarium, and behaves 

 in most respects like an adult animal. The eyes are dull brownish-black, without 

 iridescence. 



When examined again on August 13 this lobster had molted, now for the tenth 

 time, and was 28 mm. long. The general color was dark brownish-green, with 

 reddish-brown on the large chelipeds, as before. The white or light color of the 

 pleura of the first abdominal segment and tail-fan is obscured or has disappeared. 

 The shell pigments are now more abundant, and the cuticle has lost its transluceucy 

 in consequence. 



The following measurements illustrate the growth of some of the parts: 



Measurements of lobster No. 5, in truth 

 stage. 



Millime- 

 ters. 



Measurements of lobster No. 5, in tenth 

 st age. 



Millime 

 ters. 





28 

 13 

 C.4 



34 

 25 



5.5 

 10.5 



3.5 



5 





11 

 3 



5.7 

 4 



3.3 

 2 



5 

 4 

 2 





Greatest breadth of cutting chela 



Length of dactyl of cutting chela 



Greatest width of carapace 



Length from tips of extended cheli- 

 peds to end of telson 



Length of antennary tlagellum 





Length of terminal fringe of hairs. . . . 

 Greatest width of abdomen at second 



Greatest breadth of crushing chela... 

 Length of dactyl of crushing chela. . . 









Lobster Xo. 6 (table 35). — This was the only survivor out of a considerable number 

 of lobsters hatched early in the season of 1892, and when first examined — about the 

 first week in August — measured 18.5 mm., and was probably in the seventh stage. At 

 this time a slight difference in the large claws could be detected, which increased 

 with subsequent molts. There is nothing noteworthy in which this young lobster 

 differed from those already described. (See No. 38, table 34.) 



Lobster No. 1 (table 33). — I have referred to this young female lobster, which was 

 hatched about June 20, 1893, and was alive when I left Woods Hole, August 0, 1894. 

 It was therefore 412 days old, and allowing it to have attained the length of 28 mm. 

 at the tenth molt — the average length of three individuals known to have reached 

 this stage — it must have molted thirteen times, which I am confident is not far from the 

 truth. It is probable that no molts occurred during the winter, the last two recorded 

 having taken place May 21 and June 18, 1894. 



The brilliant color is now wholly due to the pigments of the shell, which is no 

 longer transparent, and the color pattern is so complicated that it almost baffles descrip- 

 tion. The body is light umber, freely speckled and mottled with darker shades. Tlie 

 appendages are reddish-brown and slightly translucent. Small light areas or suffu- 

 sions are scattered over the body. The tendon marks on the carapace corresponding 

 to those seen in the fifth and sixth stages are prominent, that below the cervical groove 

 being over a millimeter in diameter. The pleura of the first abdominal ring are snowy 

 white. The free edges of the segments of the body and appendages are bright blue. 

 The large chelae are tipped with white. The openings of the oviducts are clearly 

 seen and the copulatory pouch is not yet closed. The color of the appendages on 

 the under side is light reddish-brown. The tail-fan is of the same hue edged with 

 deep red. The claws, which are tufted with seta3 at their tips, show remarkably 

 little differentiation. The eyes have a dark-purplish pigment and have acquired the 

 characteristic large size and prominence of the adolescent stages. 



