414 Linnaan Society, 



PROCEEDINGS OF LEARNED SOCIETIES. 



LINNiEAN SOCIETY. 



May 6, 1845. — The Lord Bishop of Norwich, President, in the Chair. 



II Cavaliere Giambattista Amici, M. G. P. Deshayes, and Prof. 

 Karl Friedrich von Ledebour, were elected Foreign Members. 



Read the conclusion of Prof. Kolliker's memoir on the Hectocotylcs 

 of Tremoctopus violaceus and Argonauta Argo. 



In this paper Prof. KoUiker gives a detailed description of the 

 external form and anatomical structure of two remarkable parasites 

 referable from their characters to the genus Hectocotyle of Cuvier, 

 and bearing much resemblance to the Hect. Octopodis of that author. 

 Of one of these, that which is parasitic on the Argonaut, Delle Chiaje 

 has given an unsatisfactory account in his Memoirs on Comparative 

 Anatomy, under the name of Trichocephalus acetahularis ; and Costa 

 has endeavoured, in the sixteenth volume of the second series of the 

 * Annales des Sciences Naturelles ' to prove that it is only a separated 

 portion of the animal on which it is found. But this opinion is, ac- 

 cording to Prof. KoUiker, quite erroneous, all its characters indica- 

 ting beyond a doubt that it is a distinct animal. The two species 

 described were found by Prof. KoUiker at Messina, and are severally 

 named by him Hect. Tremoctopodis and Hect. Argonauta, from the 

 animals on which they parasiticaUy live. 



Prof. Kolliker enters into a particular statement of the reasons 

 which have induced him to believe that these Hectocotylce are in 

 reality the males of the Cephalopods on which they are found ; of 

 which reasons he gives the foUowing summary : — 



1 . The Hectocotylcs have arteries and veins, a heart and branchiae ; 



and hence it is improbable that they should be Epizootic 

 Worms. 



2. Hect. Argonaut(B and Hect. Tremoctopodis bear a close relation to 



the Cephalopoda in general, and more especially to the genera 

 on which they are found ; inasmuch as they have — 



a. The same spermatozoa ; 



h. Contractile pigment-cells ; 



e. Similarly formed and similarly organized suckers ; 



d. The same remarkable arrangement of the muscular fibres 



— the Hectocotyl(E in the muscular envelope of the body, 



the Cephalopoda in their arms. 



3. Among 280 Argonauts examined not a single male was found. 



4. Nevertheless the males must be very numerous, inasmuch as 



nearly all the Argonauts carry impregnated ova. 



5. The HectocotylcB live in the neighbourhood of the female sexual 



organs of their Cephalopods, and are all males, 



6. The eggs of the Argonaut contain, according to Madame Power 



and Maravigna, embryos perfectly similar to the Hect. Argo- 

 nautce. 



