414 Linnean Society. 
PROCEEDINGS OF LEARNED SOCIETIES. 
LINNZAN SOCIETY. 
May 6, 1845.—The Lord Bishop of Norwich, President, in the Chair. 
Il Cavaliere Giambattista Amici, M. G. P. Deshayes, and Prof. 
Karl Friedrich von Ledebour, were elected Foreign Members. 
Read the conclusion of Prof. Kélliker’s memoir on the Hectocotyle 
of Tremoctopus violaceus and Argonauta Argo. 
In this paper Prof. Kolliker 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 acetabularis ; 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. Kolliker, quite erroneous, all its characters indica- 
ting beyond a doubt that it is a distinct animal. The two species 
described were found by Prof. Kolliker at Messina, and are severally 
named by him Hect. Tremoctopodis and Hect. Argonaute, from the 
animals on which they parasitically live. 
Prof. Kélliker enters into a particular statement of the reasons 
which have induced him to believe that these Hectocotyle are in 
reality the males of the Cephalopods on which they are found ; of 
which reasons he gives the following summary :— 
1. The Hectocotyle have arteries and veins, a heart and branchie ; 
and hence it is improbable that they should be Epizootic 
Worms. 
2. Hect. Argonaute 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 ; 
b. Contractile pigment-cells ; 
c. Similarly formed and similarly organized suckers ; 
d. ‘The same remarkable arrangement of the muscular fibres 
—the Hectocotyle 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 Hectocotyle 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, embrycs perfectly similar to the Hect. Argo- 
naute. 
