OF CONCHOLOGY. 277 



ring to to the subject, says : " It is now known that in the egg 

 of the Argonauta the rudiments of the shell exist." M. Chenu, 

 also, assures us that, under the microscope, Prof. Duvernoy dis- 

 covered a distinct shell in the embryo, yet, Sir Everard Home 

 not only questioned the existence of a shell, but asserted the 

 contrary. Again, we are told that when the Piscina of Portici 

 was placed at the disposal of Poli, he witnessed the curious mech- 

 anism by which the egg is expelled from the uterus, already hav- 

 ing a shell, and satisfied himself, by following their developement 

 day by day, that the shell existed in the embryo and grew with 

 the animal. 



Now, in " Observations on the Argonauta" by Prof. Owen, 

 he declared that the secretive glands peculiar to this animal are 

 found alone in the velamenta. 



This, of course, is not a direct contradiction, but it supports 

 the statement of Madame Jeannette Power, who positively as- 

 serts, as a result of her experiments at Messina, that in twenty- 

 five days after oviposition, the young Argonaut comes forth a 

 naked cephalopod, and that in twelve days thereafter the two 

 velamenta become dilated at the extremity into a pair of mem- 

 branous webs, and commence forming a thin filmy shell. 



It is not my intention to decide which of these prescriptions 

 should be accepted. It would be well, perhaps, if either dose 

 were taken cum grano salis. 



There are many other problems connected with the history of 

 this remarkable creature that are equally puzzling in their 

 nature. I will notice but one of these, however, which is the 

 generally accepted theory that the shell of the Argonaut is con- 

 structed only by the female of a shell-less cephalopod, for the re- 

 ception of her eggs. If this theory be correct, it unavoidably 

 follows that the male is destitute of a shell ; yet Madame Power 

 declares as a fact, without exception, that after the specified 

 number of days had elapsed the two velamenta became dilated 

 at the extremity, and commenced forming a thin, filmy shell. 

 Now, if shells are produced by females only, why was it that 

 no males were hatched from the eggs in Madame Power's aqua- 

 rium ? 



