228 



HARDWICKE'S SCIENCE-GOSSIP. 



and rudimentarj' appendages have appeared upon 

 the second to the fifth segments of the abdomen. 

 In the third stage, the animal is about half an inch 

 long, and has begun to lose its Mysis-likc (sc/tizo- 

 podal) appearance, and to assume some of the 

 features of the adult. 



Fijj. 15". Embryo of Lobster, x 20 tlia. some time before 

 hatching, removed from external envelope, and shown in 

 a side view : aa, dark green yolk mass still unabsorbed; 

 b, lateral margin ot the carapace marked with many den- 

 dritic spots of red pigment ; c, eye; d, antennula; e, 

 antenna; /, external maxilliped; g, great cheliped, which 

 forms the big claw ot the adult; h, outer swimming 

 branch or exopodus of ditto; i, the four ambulatory legs 

 with their exopodal branches; U, intestine; I, heart j 

 m, bilobed tail, seen edgewise. 



There are probably two succeeding stages before 

 the adult form is attained. One is described by 

 Mr. Smith, while the first of the two he supposes to 

 have existed, but has not discovered. After this, 

 ihe animal ceases to swim on the surface, and later 



vity, on its own kind. In the first stage of the 

 adult form, when the animal is about three-fifths of 

 an inch in length, it still differs from the adult so 

 much that it would be regarded as a different genus I 

 "In this stage, the young lobsters swim very 



Fig. 158. First larval or mysis stage of the Lobster, enlarged 

 in length from i an inch. 



in the summer it seeks the bottom of the sea. It 

 feeds on the young of various animals, the larva3 of 

 other Crustacea, and when much crowded in capti- 



Fig. 159. Back view of ditto (enlarged as before). 



rapidly by means of the abdominal legs, and dart 

 backwards when disturbed with the caudal append- 

 ages, frequently jumping out of the water in this 



Fig. l6o. Cephalo-thoracic leg of the second pair, x iio dia. 

 a, exopodus; i, epipodus; c, branchial appendages. 



way like shrimps, which their movements in the water 

 much resemble. They appear to live a large part of 

 the time at the surface, as in the earlier stages, and 

 were often seen swimming about among other sur- 

 face animals." Mr. Smith thinks the young pass 

 through all the stages he describes in the course 

 of a single season. Those in the last stage men- 



