BRITISH KNTOMOSTIMOA. 



figures of the young :it d'.fl'ercnt. stages of their growth ; 

 but after having watched them for about tifleen days, he 

 likewise appears to have desisted from further inquiry. 



Notwithstanding this, M filler could not persuade him- 

 self that such dissimilar creatures could be the same 

 animal, and he has accordingly, without giving sufficient 

 credit to these illustrious men, or watching the hatching 

 and progress of the young himself, formed these imperfect 

 creatures into two distinct genera, which he has called 

 Ts'auplius and Amymone.* Hamdohr and Jurine, how- 

 ever, have both rectified this mistake, and fully corrobo- 

 rated the assertions of Leeuwcnhoek and !)c fJecr, by 

 following out the transformations in all their extent. 



The time occupied in this process varies much accord- 

 ing to the season of the year and the temperature. This 

 latter 1 have found produces an amazing difference in the 

 duration of the period so occupied, and 1 have no doubt 

 also, from myown experiments, that the process has been re- 

 tarded or hastened, just as thevessel in which they have been 

 kept has been placed in a light or dark situation. Jurine 

 says, in the case of the Ct/clops f/trf///ricor/iix, this process 

 has always lasted twenty da\ s ; and in a scries of very care- 

 ful experiments which he made in February and .March, 

 he found it extend to twenty-eight da\s. For the first 

 eight days they underwent little or no change ; between 

 the eighth and thirteenth, the body appeared a little more 

 elongated : between the thirteenth and nineteenth, the 

 Hue of demarcation between this increa.se of length and 

 primitive si/e was traceable by a line of a brown colour, 

 and the insect had acquired a third pair of feet : between 

 the nineteenth and twenty-fifth, no great change took 



* Entomost., pp. 39-4:8. It is staled 1>\ Ldreille, and echoed l>\ some 



other \\riters, Iliat the Amymmir of Mnller is the vnimi: of 1 lie ( '\elops. in 

 its earliest -lute, \\lien it lias as \et onK fmir leirs, and lliat \\lien it reeeixes 

 llic additional pair it thru becomes llie Xanplins. This i.s not correct. The 



diil'creiit species nf ilic Ain\ nnn'c arc the young of the (7. minutus in differenl 



. and of one in- I \\ o marine species; and never assume the form nl the 



Nauplius. 



e <'i/c/<i/ 



' Midler. Tlie .\,ntf,liiis 1,,;i,-t,;ilns 1 lia\e ne\er -i'i-|i, and dn ii'il know. 



mplins. 'I'he Nanplins (at least ilie Navplius saltatorius) is the young of 

 i he Cyclops quadricornis, \thich &\ its earliest stage resembles fig. 3 of plate I 



