288 THE CEPHALOPODA. §§ 251. 252. 



CHAPTER VII. 



CIRCULATORY SYSTEM. 



§251. 



The circulatory system of the Cephalopoda does not appear more highly 

 developed than that of the other Mollusca.'" However, this subject is still 

 deficient in creditable observations, and especially in those relating to the 

 absence of completely-closed vessels. 



The blood is usually colorless, or of a green-bice, or violet-bice color, and 

 contains, proportionably, numerous round corpuscles enclosing many gran- 

 ules most of which are colorless, but with a few, scattered here' and there, 

 of a violet hue.*^> 



§ 252. 



The Central organ of the circulation consis^ts, with all the Cephalopoda, 

 of a simple ventricle, situated in the centre of the cavity of the body, and 

 surrounded with a pericardium. It is round, or oblong,*^' and serves as an 

 aortic heart. 



With Nautilus (Tetrabranchiata), this organ receives, on each side, 

 two branchial veins ; while with the Dibranchiata there is one vein 

 only, and the heart sends off a superior and an inferior aortic trunk. *-^ The 

 mouth of the veins and the origin of the arteries are furnished with 

 valves.*^' The Ascending aorta first sends two branches to the mantle, 

 then gives off branches to the liver, to the upper portion of the digestive 

 canal, to the inferior salivary glands, and to the funnel. Behind 

 the cephalic cartilage it bifurcates, forming a ring embracing the 

 upper extremity of the oesophagus, and from which arise two arteries for 

 the ocular bulbs, **^ eight or ten for the arms, and many small branches 

 for the parts of the mouth. ^^> The Descending aorta furnishes branches to 



1 See Milne Edwards, and Valenciennes, posterior part of the body •, it is large in tlie gen- 



Oompt. rend. XX. 1845, p. 261, 750, or Frnhep''s era with a short body, and elontrated in those of a 



neue Notiz. XXXIV. p. 84, 258 ; also Milne long body. According to Kolliker (Ann. of Nat. 



Edwards, Ann. d. Sc. Nat. III. 1845, p. 341. Hist. XVI. p. 414), Hectocotijlus has also a 



This last author has also described (Ann. d. Sc. heart communicating with arteries and veins, but 



Nat. VIII. p. 53), the circulatory system of the he says nothing of its locality. 



Loligina, which is interrupted by a large sinus ; 2 See Owen, On the Nautilus, PI. VI. fig. 1, or 



but he makes no mention of the aquiferous system. Isis, Taf. IV. or Ann. d. Sc. Nat. XXVIII. PI. III. 



As of late there is increasing evidence for the fig. 2 ; Brandt, loc. cit. Taf. XXXII. fig. 22 ; The 



opinion, that, with various mvertebrate animals, Catal. of the Physiol. Ser. 11. PI. XXII. (Sepia); 



the blood-system communicates externally at cer- and Van Be.neden, loc. cit. PI. III. fig. 5 (Ar- 



tain points on the body, and can therefore receive gonauta). 



water into its interior, it is now important to inves- Often the two branchial arteries are widely di- 



tigate the direct or indirect relations between this lated before entering the heart, and these dilata- 



and the aquiferous system which is so widely tions may be regarded as auricles, 



spread through the MoUusks, the Worms and the 3 See Cu-vier, Mem. p. 22, PI. II. fig. 4 (Octo- 



Zoophytes. Jt may be that this aquiferous system, pus); and Owen, Cyclop. I. p. 541, fig. 227 



if it really communicates with the blood system, (pni/rJioteuthis). 



corresponds to a lymphatic apparatus, although it 4 For the distribution of the ophthalmic arteries 



scetfis hardly reasonable to suppose that canals, see Krohn, Nov. Act. Nat. Cur. XIX. pt. II. p. 



which carry a portion of the nutritive fluids, should 47. 



open externally.* 5 Dclle Cliiaje, loc. cit. Tav. LXXX'STII. XO. 



a Wagner, Zur vergleich. Physiol, d. Blutes. XCII. XCIV. (or 20, 28, 22, 24) has represented 



Hft. I. p. 19 ; and Delle Cliiaje, Descriz. I. p. 57. in detail the arterial system of Octopus vulgaris, 



I The form of the heart depends upon that of the Sepia officinalis, Loligo vulgaris and sagittata. 



* [ § 251, note 1.] For Milne Edwards'' beautiful figures see K^gne anim. loc. cit. PI. l'>, 1 

 (Octopus). — Ei). 



