^ 252. THE CEPHALOPODA. 289 



f- ^ • _ 



the stomach, the small intestine, the rectum, the branchiae, and the genital 

 organs ; the artery of these last, however, sometimes arises directly from the 

 heart. 



Nothing positive can now be said as to the terminal relations of these 

 arteries ; — that is, whether they are directly continuous with the venous 

 radicles by means of a capillary system with proper walls, or whether they 

 terminate by orifices so that the blood is efiiised immediately into the paren- 

 chyma of the body.^^' 



The Venous system begins in the difierent parts of the body by numer- 

 ous small vessels, of which we are still ignorant whether they are continu- 

 ous with the terminal arterioles, or whether they commence by themselvcH' 

 with proper orifices. Their radicles unite and form longer branches which 

 finally open into a large Sinus. One of these sinuses, which is of a circular 

 form, surrounds the upper extremity of the oesophagus, and receives the 

 veins coming from the eyes, the arms,*"' and the parts of the mouth. From 

 this sinus arises another, of an oblong form, which, since it extends into 

 the cavity of the body and receives the different veins from the viscera, 

 may be called a Vena cava stiperior. In the centre of the body it divides 

 into two large venae cavae which extend on each side to the base of the 

 branchiae® and terminate in the two so-called branchial hearts.® These 

 two veins receive, also, two trunks, which bring the blood from the mantle 

 and are often dilated into two large sinuses. '^^' 



The distinct, but often very thin walls of the venous sinuses, are some- 

 times so intimately blended with the adjacent organs, that these sinuses may 

 be easily taken for wall-less lacunae.*"' 



6 Milne Edwards and Valenciennes (loc. cit.) the cavity of the body, and there are many circum- 

 throw no light on these questions. It is moreover stances in favor of this view. It is, therefore, to be 

 singular that in the numerous and often very de- regretted that Milne Edwards did not, in his re- 

 tailed figures of Delte Chiaje of the vascular sys- searches, pay more attention to the aquiferous By»- 

 tem of Cephalopoda, he has nowhere represented tem which is spread through the whole body or 

 in the least a capillary net-work between the arte- the Cephalopoda, and thus, for the present at 

 ries and veins ; while Kblliker (Entwick. der Ce- least, prevent the objection, that these aqueous 

 phal. p. 81), declares that he has seen numerous reservoirs should be confounded with the venous 

 oapillary vessels in the embryos of Sepia. sinuses. The lymphatic reservoirs which, according 



7 All the arms of the Cephalopoda have two to Erdl (fVieffmann''s Arch. 1843, I. p. 163) sur- 

 venous trunks. Lebert and Robin (3Iu.ller''s round, and can be injected by means of the arteries, 

 Arch. 1846, p. 130) have observed, in the venous are also, perhaps, venous sinuses. An observation 

 system Sepia officinalis, a valve preventing the of Owen (On the Nautilus, p. 27, PI. VI. fig. 1, 

 reflux of the blood towards the head. No. 1', or Isis, p. 24. Taf. IV. or Ann. d. Sc. Nat. p. 



8 With Nautilus, this sinus is divided into four 121, PI. III. fig. 2, No. l^), and of Valenciennes 

 venae cavae (Owen, loc. cit.). (loc. cit. p. 287), that the large superior vena cava 



9 The so-called Branchial hearts of the dibranch- communicates with the abdominal cavity by no- 

 iate Cephalopoda have no muscular fibres, but merous orifices, is of much importance. For, in thSs 

 have a very glandular aspect, and are in close re- way, this vein must be regarded as a large blood- 

 lation with the urinary organs ; see below, § 255. reservoir, conducting, very probably, the "nutritive 



1" De/le Chiaje, loc. cit. , Tav. LXXXVIT. fluid, after its transudation through the intestinal 



LXXXIX. XCI. XCIII. (17, 27, 21, 23), has also canal, into the general blood current, 

 figured with many details the venous system of The pericardium of the Cephalopoda sustains, 



Octopus, Sepia, and Loligo. perhaps, analogous relations to the blood-system, 



11 It is, therefore, difficult to decide if the large for, with Nautilus, it is said to communicate with 



cavities which Milne Edwards (Ann. d. Sc. Nat. the abdominal cavity, and with the principal vena 



III. loc. cit. PI. XIII.-XVI.) has injected, were di- cava, with the other Cephalopoda ; see the conclud- 



lated veins or simple lacunae. In this last case, ing paragraph of note 1, § 251. 

 the venous system would communicate directly with 



25 



I 



