BOOK ELEVENTH. 



CEPHALOPODA 



CLASSIFICATION. 



§ 230. 



The Cephalopoda present, in their organization both internal and 

 externa], so many peculiarities which distinguish them from all the other 

 MoUusca, that it is necessary to consider them in a class by themselves, 

 although their genera are not numerous. 



It is, moreover, necessary to state why we here regard the different forms 

 of Hectocotyliis which hitherto have been considered as parasites of these ani- 

 mals, as the males of certain Octopoda.'^^ The researches of ifoZ/iA-tr have 

 led us to make this change. This naturalist founds his opinion upon the 

 following convincing reasons:*-' The specimens o'i Hectocotyliis have bran- 

 chiae, and a heart with arteries and veins, and they cannot, therefore, be 

 regarded as Hehuinthes. On the other hand, they have, in common with the 

 Cephalopoda, the contractile chromatophoric cells of the skin, and the same 

 kind of spermatic particles and suckers ; and the muscular substance of 

 their bodj'^ is arranged exactly like that of the arms of the Cephalopoda. 

 All of them are males, and the Cephalopoda, with which they are connected, 

 are all females; finally, the embryos found in the eggs of certain Octjpoda 

 exactly resemble them. AVhoever has had the opportunity of examining the 

 species yet known, viz : Hectocotyliis argonautae, octopodis, and tremoclopo- 



1 At present there are known two or three species XVIII. 1823, p. lit, PI. XI. A. fig. 1 5, or Fro- 



of these singular bjiii;?s resembUuii the tjrn-off riep's Njt. X.KVII. 1830, p. 6, fijr. 16-lJ, or Isi.«, 



arms of the Ojtopula, and which hve in tlie cavity 1832, p. 559, Taf. IX. fi^'. 1-5) shjuld b^; fjund in 



of the mantle of certain Octopoda, attached by the cavity of the mantle of Octnpii.i sraniilatus 



the means of suckers. Hectocotyliis ar^onautie (Lamarck). It is i)r»bahly identical with Octopus 



was first described quite imperfectly by Delle Chi- tubercidatus of Delle C/iiaje (Octopii.t yerany, 



aje (Menur. &c. II. p. 225, Tav. XV'I. fig. 1, 2, Jf'aspipr), which lives in the Mediterranean Sea, 



and Isis, lSo2, Taf. X. fig. 12, a. b.) under and perhaps, also, with Tremoctopus vio/aceus. 



the name of Trinlioceplialus acetabularis. An- If this laslJ is not so, there is then a thii-d species 



other description by Costa (.\un. de Sc. Nat. of ffectocotylus, viz : the male of Tremoctopus 



XVI. 1841, p. 184, PI. XIII. fig. 2, a.-c.)has not vio/aceus. 



added much to our knowledge of the real nature of ^ S;e Kolliker, On the Hectocotyliis of Tre- 



this animal. Another species, Hectocotyliis octo- moctopiis violaceiis, and Arsronauta argo, in 



podis, established by Cuvier (Ann. d. So. Nat. the Ami. of Nat. Hist. XVI. 1845, p. 414. 



