LERNEAD^. 319 



from one place to another, how is it that we thus find 

 them fixed upon these fishes, mature and possessing ova? 

 Blainville answers this question, by saying, " it is difficult 

 to conceive how these animals, which spring from eggs, 

 are fixed upon fishes without admitting that in their young 

 age they possess a little motion." J\I. Surriray had at 

 that time demonstrated to Blainville the existence of the 

 young when just hatched ; but less importance was at- 

 tached to this discovery than it deserved ; and it was not 

 till Nordmann corroborated the fact, and followed it up 

 by his more patient researches, that we were enabled to 

 answer the question fully. 



The circumstance that the Lerneadse soon die after being 

 taken from the fish that has served them for nourishment 

 and a habitation, certainly throws great difficulty in our 

 way of observing the development of the young ; but we 

 now know that when hatched, and for some time after- 

 wards, the young Lerneada? are nimble and active, and 

 possess both the organs of motion and the faculty of 

 using them. When they first come out of the egg they 

 are of an oval shape, and very much resemble the young 

 of the Cyclopidse. They possess a large eye, situated in 

 the centre of the anterior and upper part of the body, and 

 are provided with two large pairs of swimming-feet, and 

 a pair of jointed antennae. As in the Cyclopidse, these 

 young Lerneadse cast their skin repeatedly before they 

 arrive at maturity. After the first moulting, the body is 

 seen plainly divided into two parts, the anterior of which 

 is furnished with three pairs of hooked feet, and the pos- 

 terior with two pairs of swimming-feet. No doubt there 

 are a good many stages of development to go through 

 before they assume the mature form, but it has not yet 

 been possible to follow them out. It is not the least 

 curious part of the history of these singular-looking ani- 

 mals, that the young should thus stand on a higher stage 

 of development than the mother ! and that their progress 

 from youth to maturity should be in the directly opposite 

 ratio to that of all the other Crustacea. At what period 



