150 OBSERVATIONS ON THE ARGONAUT. 



after the sailing ones, and on the sixth day they had already 

 formed the first lamina of the shell, exceedingly soft to the 

 least pressure of the finger. 



The eggs are attached to the interior of the spire, and when 

 excluded by the above-named animals, remain between the 

 roof of the spire and the mantle of the mother. From these 

 observations the result is that the newly-born poulp has no 

 shell, and, it may be concluded, has none in the egg. The 

 observations of Poli therefore do not correspond with the ex- 

 periments made by me on purpose ; and if not speaking of 

 so celebrated a man, I should venture to say that the internal 

 membrane of the egg was mistaken by him for the supposed 

 rudiment of the shell. 



I much wished to discover whether the little poulp could 

 by itself, without extraneous aid, begin to work the struc- 

 ture of its shell, or whether the parent took part in the origi- 

 nal formation, the proper organs for secreting calcareous mat- 

 ter in the former not being as yet developed. With this view 

 I took divers argonauts at the time of their fecundation, and 

 cautiously cut off the spire. In the direction of its axis I 

 found, in one, a little poulp rolled up, and near the apex. — 

 Observing it attentively I perceived that between it and the 

 bottom of the spire of the parent shell there was a thin mem- 

 brane, disposed in the same form as the curve of the spire, 

 and fitted to the rolled-up little poulp, as if the gluten in 

 which the whole mollusc was embedded, pressed between it 

 and the end of the spire, became consolidated into a fine 

 membrane in the same form as the spire, and embraced 

 the new little poulp. 



The 10th of September 1835, wishing to continue my ex- 

 periments, I inclosed in the cage some argonauts at the time 

 of their fecundation, taking care to examine them every fourth 

 day, and with the usual precautions in handling them, for 

 they are very irritable, and suffer so much from being dis- 

 turbed that they soon die after it. I therefore took them up 

 in a basin, by immersing it in the water underneath, which I 

 thus brought up together with them, and posted myself so 

 that I might observe all their movements without their seeing 

 me. 



On the 14th I found in one of the shells a little poulp four- 

 teen lines in length. Searched others, and in some found 

 little poulps, in others none. 



On the 18th of the same month, visiting them as usual, 

 found two parent poulps dead. In the one in which I had 

 first seen the little poulp I found it had already passed into 

 the spire. 



