L 9 ] 



II. Some Observations upon the Structure of two new Species of Hectocotyle, 

 parasitic upon Tremoctopus violaceus, D. Ch., and Argonauta Argo, Linn. ; 

 with an Exposition of the Hypothesis that these Hectocotylae are the Males 

 of the Cephalopoda upon which they are found. By A. Kolltker, Pro- 

 fessor of Physiology and Comparative Anatomy in the University of Zurich. 

 Communicated by Robert Brown, Esq., V.P.L.S. 8^c. 8^c. 



Read April 15th and May 6th, 1845. 



Whilst visiting Messina and Naples during the summer of 1842, 1 found 

 two worms resembling the Hectocotyle Octopodis, described by Cuvier as found 

 upon the Octopus granulosus, Lam. ; the one upon the Tremoctopus violaceus, 

 Delle Chiaje (Octopus velifer, F6r.), the other upon the Argonauta Argo, L. At 

 first sight I took them for epizootic worms, to which, from their white colour 

 and numerous suckers, they bore a great resemblance ; but when I examined 

 them more accurately, I met with so many peculiarities, a few of which I will 

 here mention, namely the existence of a heart, arteries and veins, branchiae, and 

 coloured contractile pigment-cells, that at length I was compelled to abandon 

 that idea. Proceeding with my examinations, I soon found that the animals 

 were all males ; and remembering that that sex of the Argonauta and Tremoc- 

 topus was not as yet known, I supposed that I had discovered the males of 

 those Cephalopoda. I must confess that at first I did not place much reliance 

 upon this conjecture, for the great dissimilarity between the supposed sexes 

 surprised me so much that I scarcely dared to believe it to be well-founded. 

 However, as I proceeded further with my researches, I found more and more 

 to strengthen my supposition, so that finally I was led to regard it as very 

 probable. But before proceeding to submit the arguments on which I formed 

 my opinion, I propose to give a slight sketch of my anatomical researches 

 with respect to the above-mentioned animals. 



VOL. XX. c 



