1886,] Embryology. 741 
heralded by the fourth ecdysis or molt. The telson now closely 
resembles that of the adult, and on either side of it the broad 
brown in some cases, so that the animal is no longer so trans- 
Parent as during the preceding stages. 
Sixth stage-—This stage is attained between five and six weeks 
after hatching and, like the foregoing, is preceded by —_ 
The latter, unlike the previous molts, is hard and brittle, bluish 
in color and retains the form attained by the animal at the end of 
the preceding stage. The young lobster now measures 19™™ 
from the tip of the still bifid rostrum to the tip of the telson; 
22" from the tips of the extended chelipeds to the end of the 
abdomen. The antennz are now considerably longer than the 
cephalothorax, or proportionally almost as long as those of the ~ 
adult ; the total length of the animal from the tips of the extended — 
antenne to the end of the telson is now 29™™ One of the chela is 
now also perceptibly larger than the other. The animal has not | 
at, however, assumed the adult condition, as there are still no _ 
_ ppendages developed on the first abdominal segment. — 
Seventh stage—This is also preceded by an ecdysis, and the 
_ young animal now measures 22™™ in length from the tip of the 
: aS the end of the telson ; 36™™ from the tip of ap ae on 
aq 0 the tip of the telson. The pair of appendages on the first 
dominal ring have now appeared as very short rudiments which 
ee ESR 3 
