SEA-B UTTERFLIES. 3 1 9 



their relatives could be seen laying eggs, with transparent shells, 

 which resembled rosaries or long pods, in the spaces of which 

 the eggs swam in a clear liquid. Do they lay these eggs because 

 they are comfortable in the vessel, or in order to rid themselves 

 of what is a burden in their straitened captivity ? While this 

 question is still unanswered, it is certain that such strings of eggs 

 and pods are also found drifting in the open sea, that the eggs 

 which are laid in captivity are usually fertilized, and that the 

 development of the embryo can be followed under the microscope 

 — at least, till the point when the larvae, which go through many 

 metamorphoses, leave the shells to swim in the sea. These do not 

 resemble the parents, but the larvae of creeping sea-mollusks, and 

 swim by means of a ciliary apparatus which grows on the head, 

 and afterward, when the wings have been formed, is repressed. 

 The free larvae have not been successfully raised any further in 

 captivity. Probably they die of hunger, for it is impossible to 

 feed them. But we can fish them out of the sea in a net, and can 

 compare from the various forms found among them the succession 

 of single steps in their growth to the adult state. This is, indeed, 

 not always easy, for, on the one hand, the larvae of different species 

 are often very much alike, and, on the other hand, the currents 

 do not always fetch what is wanted, so that many observers have 

 to wait year after year to continue their observations and bring 

 them to a conclusion. 



Dealing with the pelagic animals that swim on the high sea 

 is a delicate matter, and, despite the most careful researches, the 



Fig. 3.— Creseis acicula. Fig. 4.— Hyalea tridentata. Fig. 5.— Cleodora lanceolata. 



cause of their appearance and disappearance has never been ascer- 

 tained. In the years from 1850 to 1852, which I spent in Nice, 

 and when I fished with my fine net at least twice a week in the 

 Bay of Villafranca, I only found a few species of needle-butterflies 

 and related species. Cymbulice, which could not have escaped me 

 then, I first found at a visit in the Easter vacation of 1867, when 

 they were very numerous. Messina is the Mediterranean station 



