379 



found ; and yet the males must be very numerous, as almost all 

 the Argonauts carry impregnated ova. In 1825, Delia Chiaje, 

 at Naples, described and figured, under the name of Tricoceph- 

 ahis acetabular is, a small animal, supposed a parasite, on the 

 Argonaut ; he placed it among the Helminthes or Trematode 

 Worms, although it had a double row of suckers, by which it 

 fixed itself to the skin of the Argonaut; similar animals were 

 afterwards described by Cuvier under the name of Hectocotylus. 

 Dujardin seems to have been the first to perceive the true 

 position of these animals, thinking them parts detached from a 

 Cephalopod for purposes of fecundation. In 1842, Koelliker 

 advanced the opinion that these animals were the males of the 

 Cephalopods on which they were found. He maintained * that 

 they have arteries and veins, a heart and branchiae ; that they 

 have the same spermatozoa, contractile pigment-cells, suckers, and 

 remarkable arrangement of the muscular fibres, as exist in the 

 Cephalopods on which they are found ; that they are all males, 

 and live in the neighborhood of the female organs ; and (what is 

 probably not true) that the embryos found in the eggs of some 

 Octopods exactly resemble them. 



Von Siebold {op. cit. Book 11), following Koelliker, considers 

 the Hectocotylus as the male of an Octopod, though he differs 

 from him in regard to certain points of their structure. Both of 

 these authors have fallen into errors which have been corrected by 

 M. M. Verany and C. Vogt,t the latest writers on the subject, to 

 whom we must refer for details and figures ; the latter con- 

 sider the Hectocotyli, not as stunted males, but as detached arms 

 of Cephalopods organized in a special manner, having neither 

 the intestine nor the heart indicated by Koelliker. M. Verany 

 found in the Mediterranean an Octopus which had, in the place 

 of the right arm of the third pair, a vesicle implanted on a small 

 pedicle furnished with suckers ; on other specimens, this arm 

 was abnormal, instead of a vesicle, the pedicle supporting a very 

 large arm terminated by a globular body resembling the Hec- 

 tocotylus of Cuvier ; this abnormal arm was easily detached, and 



* Trans, of the Linuean Society, Vol. 20, London, 1846, pp. 9-21. 

 t Annales des Sciences Xaturelles, Tome 17, 1852, Paris, pp. 147-188. 



