^ 252. THE CEPHALOPODA. 281> 



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 efiused immediately into the paren- 

 chyma of the body.^''' 



The Venous system begins in the different 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 themselves 

 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 diflerent veins from the viscera. 

 may be called a Ve?ia cava siiperior. 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 sniuses.'"^' 



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 circura- 

 throw no light on these questions. It is nioreovsr stances la favor of this view. It is, tlieref ire, to b& 

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

 tailed ügureä oi Delle Chiaje of the vascular sys- searches, pay mire attention to the a(iuif>,'rous sys- 

 tem of Cephalopoda, he has nowhere rejirjsenteJ teni winch is spread tlirough the whole body of 

 in the least a capillary net-worli between tlie arte- the Cephalopod i, and thus, for the present at 

 ries and veins; while Aö//i/ier (Entwicii. der Ce- least, pi event the olyection, that these aqueous 

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

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



^ All the arms of the Cephalopoda have two to Erdl (tVie^rnann^s Arch. 1843, I. p. 163) sur- 



venous trunks. Lebert and Robin (Muller^s round, and can be injected by means of the arteries. 



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



system Se^ia officinalis, a valve pi-eventing the of Owen (Jn the Nautilus, p. 27, PI. VI. fig. 1, 



refiu.x of the blood towards the head. No. 1, or Isis, p. 'H. Taf. IV. or Ann. d. Sc. Nat. p. 



8 With Nautilus, this sinus is divided into four 121, PI. I±I. tig. 2, No. 1*), and of yalenciennes 



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



y The so-called Branchial hearts of the dibranch- communicates with the abdomic.al cavity by nu- 



iate Ceplialopoda have no mviscular fibres, but merousoriiices, is of much importance. For, in this 



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- 



10 Delle Chiaje, loc. cit. Tav. L.V.XXVrr. 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 jjericardium of the Cephalopoda sustains. 



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



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

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

 III. loc. cit. PI. XIII.-XVI.) has injected, weredi- cava, with the other Cephalopoda ; sec the conclud- 

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



the venous system would communicate dii'ectly with 



25 



