ARQONAUTA ARGO AND THE HBCTOCOTYLI. 53 



to drop off on being touched, resembled the Hectocotyhis Octo- 

 podis of Cuvier*, and Verany concludes from thence that this 

 Hectocotylus Octopodis is a deciduous arm bearing male organs 

 which are probably periodically developed. With regard to the 

 Hectocotyli of the Argonaut and of Tremoctopus on the other 

 hand, Verany beUeves that they cannot be arms of the corre- 

 sponding Cephalopoda. 



These statements rendered the subject of the Hectocotyli far 

 more difficult than ever. It could hardly be believed that the 

 Hectocotylus of the Octopus could be really distinct in its nature 

 from the two examined by KoUiker ; and yet upon the other 

 hand, there were many reasons for hesitating to apply the con- 

 clusions drawn from the former to the latter. The Hectocotylus 

 octopodis differs in many respects from the others ; its sexual 

 relations are less certain, while those of the Octopods to which 

 it was attached, either in the mantle or as an arm, are wholly 

 unknown ; and finally, the positive assertions of Madame Power 

 and Maravigno (see KoUiker, /. c.) seemed to prove that the 

 Hectocotylus Argonautce was developed as such in the ova of the 

 Argonaut. 



While at Messina, in the past autumn, I was very desirous of 

 repeating the observations of Madame Power; but notwith- 

 standing the examination of many thousand ova of all the Ar- 

 gonauts which I could procure, I merely found embryos of the 

 ordinary form more or less developed ; never those vermiform 

 young, whose description had led to the belief that the Hecto- 

 cotyli were developed in especial bunches of ova. 



At last, at the end of September and in the beginning of Oc- 

 tober, there were brought to me, among many very small Argo- 

 nauts which had not yet acquired a shell, a few of a quite pecu- 

 liar form. Their cephalic extremity presented a little sac, which 

 projected between the arms, as the animals swam about with 

 their peculiar retrograde movement. On closer inspection f one 

 could perceive seven arms, which all terminated in points like 

 the six lower arms of other Argonauts of the same size. The 



* Annales d. Sc. Nat. 1829, p. 147, pi. 11. 



t The relations of the parts were clearest when the animals fixed themselves 

 during life, within a glass, so that one could look from without straight down 

 upon the oval surface of the head ; or after death, by placing them in a waxen, 

 pit so as to obtain a similar view. 



