\l. MI;,, 



matophoi i.ccn found, and the hectocot yli/ed ami 



:o perform its ollice without snli-e<plent i let :i c!l llKMlt from 



iiima!. The detached heetocotyle when first discovered in 

 the ni:iiit lc <>!' 1 In- female \v;is naturally reo'arded ;is a parasitic 

 w<nii: th:it of A riroiianta leiiiir termed Trichocephalus acetabv- 



liy rhiaje .-iii:l that of Octopus I l<'<-t<><-<>! ijl nx nrtnfnnlix ly 

 Cnvier. More rocnitly it \vn> Mii>|)t>si'(l to IK- tin- riithv innli 1 



;niiiii:il of t hr cephalopod. 



In 'rrnnociopus tin- third :inn >n the ri^ht side Itrcomrs hec- 

 i vli/cd : it is then worm-like in appearance, with two \ 



re on its\-cntr;d snrlMee ;md :in ov:il MppciidiiLl'' 1 :it the 

 po-tcri-T end. The .-interior p.-ii't of the li.-u-k is tViiiLicd with ;i 

 dollhlr series of l)l';l nelli;d lil;uil'-!lt s -2^0 on each side). liefnven 

 the lil.-imcnts :in- 1 wo rows of hrown or violet. s|ots. 'I'he <>iekers 

 ( lort y on e:ieh side elosely re^'inl >le. nut :i re mneh smaller tlutn 

 those >!' the norm;d :irms. IJet.ween the snekers MH- t'onr or live 

 - >!' poi-cs. tin- openings ol' minute c;in;i!s |;issin^ into the 

 interior. Then- is ;ui nrtery and vein on each side. -ivin^ 

 l>r:iiiehe-> to the lir.-urehinl lihiments. while ;i nerve nm> down the 

 centre. The ami .<//// encloses M smnll Inil very loni- eonvolnh d 

 tnlie. ending in a mnseiilar sack which contains the spermato/oa. 



The hectoeotyle ol' the Argonaut is vei-y small, only half an 

 inch, with a filiform appendage in front -of about e<pial length: 

 ll has two rOWS Of alternate suckers, forty-live on either side; 

 lnt no liranehi;e. 



Tin- K.-ttlM-r of Nutnral Bistory, who- was certainly a first-class 

 rver, Was aeipi.-nnted with the heel oet \ 1 i/cd ai'm and its 

 t'nnetioiis. Imt his de^enerale successors for many centuries not 

 only misunderstood ll Imt hint also. 



In Octopus the hectocotylixed a rin instead of lieinu much 

 short* r than the others. MS in A r^onanta. becomes much longer. 

 It teniiin.-ite- in an ov.-d |>late, marked with iiiimer<n> trans\ 



68 and intervening pits, and this ;> connected hy ;i muscular 

 fold >f skin running Mlon^ the dorsal face of the arm \\ith the 

 w-llied liu-e. rovcrin- ,-i passage through which the -permato- 

 |)lir - are piol;illy transmitted to the terminal plate. 



It will he seen in the systematic portion of this work that aMc 

 ha\e in some -arded a> o|po>i' only 



