4S6 TRANSFORMATIONS OF INSECTS. 



such as the mandibles and the maxillse, bear a close resemblance 

 of form to the same organs in adult Crustacea, of an order lower 

 than the parent of these." (Spence Bate.) 



Many years since, Erdl stated that the young lobster was of 

 the same shape as the adult, and the metamorphosis of these 

 common Crustacea has therefore been denied. This opinion was 

 strengthened by the observation that the European fresh-water 

 cray-fish and the West Indian land crab quit the &g^ with the full 

 number of jointed limbs, and, indeed, in the likeness of their parents. 

 All these are stalk-eyed Crustacea; and what could be more natural 

 than that they should all have the same method of evolution .'' It 

 is most remarkable how dangerous it is to reason by analogy in 

 natural history, and to indulge the imagination in science. Gerbe, 

 Spence Bate, and Couch, however, have proved that the statement 

 of Erdl is not consistent with facts. Spence Bate noticed, in one 

 of his reports to the British Association for the Advancement of 

 Science, that " common as the European lobster {Honiarus 

 Diarinus) is, it is very remarkable that a very young specimen has, 

 as far as I know, never been met with." He offered a reward for 

 a very small specimen, but never received one less than three 

 inches long from the tip of the spine over the head (rostrum) to 

 the end of the tail-piece (telson). By hatching the eggs, however, 

 he obtained the first stage of lobster life, but could not keep the 

 young alive until their metamorphosis into the second. Having 

 obtained also a young lobster, eight days old, from the Hamburg 

 aquarium, he was able to state that not only is the young hatched 

 in a form distinct from that of the parent, but that it retains that 

 form for some time after its birth. 



The figures on the next page are by M. Gerbe, and the descrip- 

 tions of Spence Bate prove that they are tolerably correct. 



The Q.^% is about one-tenth of an inch in diameter, and contains 

 a yolk of a dark, almost black, green colour. The central dark eye 

 of the embryo is distinctly seen in the earlier days of development, " 

 but it is lost when the animal escapes from the Qg%. At this 

 period the young Zoca has a short pointed (Fig. 2) rostrum that 

 is at first bent back, two large eyes situated under the front 

 part of the head, and two antennae. It has mandibles without 

 joints, two pairs of maxillae, the third not being yet developed, and 



